불완전이행책임의 현대화에 대한 연구

Abstract

국제거래규범(CISG, PICC, PECL, DCFR)과 이에 영향을 받은 주요 외국(독일, 프랑스, 일본)의 최근 개정 민법이 공통된 규율대상이자 그 지향점으로 삼았던 계약책임법의 현대화를 우리 민법에서 이루기 위해, (1) 계약책임체계의 통일을 위한 불완전이행책임법의 통합가능성과 (2) 그 책임 내용으로서 민법상 개별 계약에서 제한적으로 규정된 추완청구권, 대금감액권의 활용가능성 확대를 해석론과 입법론을 통해 모색하였다. 우리 민법은 과실책임인 채무불이행책임과 무과실책임인 담보책임의 이원적 계약책임체계를 취함으로써 양 책임의 중첩으로 인한 해석론의 복잡한 전개를 야기하였는데, 그 규율대상은 불완전이행 또는 하자 있는 이행으로 인한 불완전이행책임으로 집약될 수 있다. 이와 관련 국제거래규범들과 주요 외국의 개정 민법들은 포괄개념에 의해 계약책임체계를 통일하는 한편, 불법행위책임과 달리 계약책임에서 과실책임주의를 점차 분리하는 경향을 보이고 있다. 이에 비춰 우선 제390조는 채무불이행책임의 요건에 대한 일반규정으로서 유책사유와 상관없는 채무불이행만을 규정하고 있으며, 채무불이행책임의 내용으로서는 유책사유를 요하는 손해배상의무만을 규정하고 있다고 보았다. 그 밖의 구제수단들은 개별규정 및 해석 하에서 채무불이행책임의 내용을 이룬다. 그리고 우리 민법상 불완전이행책임의 통합을 위해 객관적 요건인 불완전이행과 하자의 비교 및 주관적 요건인 유책사유의 채무불이행책임으로서 손해배상과 분리가능성을 법제사적, 비교법적, 법이론적 관점에서 살펴보았다. 이를 통해 불완전이행으로 인한 채무불이행책임과 하자로 인한 담보책임이 상호 접근함으로써 양자 사이에 본질적인 차이가 없음을 확인하고, 궁극적으로 이행보증으로서 계약책임을 채무자에게 귀속시키는 정당화 근거를 새롭게 형성할 필요를 제시하였다. 다만, 과실책임에 기초한 민법규정 간의 체계적 해석에 반할 수 있기 때문에 입법론으로 검토되는 것이 타당하고, 제390조의 고의·과실은 손해배상의 기능적 면책사유로 파악할 수 있다. 이는 2013년 민법개정시안이 유책성을 배제한 계약해제의 일반규정(제544조)을 마련함으로써 진일보하게 되었다. 불완전이행의 경우 급부실현을 위한 채권자의 효과적인 구제수단으로서 추완청구권과 관련해, 국제거래규범은 추완청구권을 채권자의 일반적인 구제수단으로 인정하고 있으며, 독일과 일본은 담보책임으로서 권리와 물건의 하자를 구별하지 않고 이를 도입하였고, 프랑스는 개별 계약의 개정을 완료하지 않았지만 계약불이행의 구제수단으로 신설한 현실이행의 강제를 근거로 추완청구권을 인정할 수 있을 것이다. 우리 민법상 추완청구권 역시 계약의 구속력에서 인정되는 이행청구권의 보조수단인 동시에 원상회복과 다른 불완전이행에 고유한 효과로서, 이행이익이 실현가능한 한 대(大)는 소(小)를 포함한다는 원칙 등 다양한 근거에 의해 채무불이행책임 및 담보책임으로 인정될 수 있다. 이때 실정법상 근거로는 그 법적 성격에 비춰 채무불이행의 구제수단인 강제이행청구권(제389조)으로 보는 것이 타당하다. 추완청구권의 세부유형으로 대체이행청구권, 부족분이행청구권, 보수청구권이 인정될 수 있고, 이종물 인도는 불완전이행의 효과로서 대체이행청구권에 의해 규율하는 것이 타당하며, 그 밖에 추완청구권의 인정여부가 문제되는 경우 추완가능성에 의해 판단된어야 한다. 추완청구권의 행사를 위하여, 하자담보책임에서 매수인의 무과실요건을 관행화된 정도의 검사의무 이행여부로 판단할 수 있지만 명문의 근거없이 하자통지의무를 요구하는 것은 부적절하다. 원칙적으로 채권자는 추완유형을 선택할 수 있지만, 체계적 해석상 상당기간을 정하여 행사하여야 하고, 매도인의 완전물급부의무와 매수인의 물건반환의무 사이에 동시이행관계를 인정할 수 있으며 완전물급부가 있기까지 매수인의 사용이익은 계약의 내용이므로 부당이득이라고 볼 수 없다. 이행청구권의 연장인 추완청구권도 급부불능 또는 채무자에게 과도한 부담이 되는 등 상당성을 결여한 경우 신의칙상 제한될 수 있고, 명문의 규정없이 책임원인을 제공한 채무자에게 추완권을 인정하는 것은 그 법적 성격에 비추어 무리가 있다. 계약의 구속력에 비추어 원칙적으로 손해배상청구권 및 계약해제권의 행사에 앞서 상당기간 추완이행을 최고하도록 함으로써 추완청구권을 우선하는 것이 타당하지만, 법문상 담보책임으로서 손해배상청구권과 추완청구권의 선택권은 매수인에게 있고 계약해제권의 요건인 계약의 목적달성불능은 추완불가능성을 전제로 엄격하게 해석하는 것이 타당하다. 2013년 민법개정시안은 채무불이행책임은 물론 하자담보책임으로 추완청구권을 명시하는 한편, 채무불이행책임의 추완청구권을 준용함으로써 그 내용과 제한요건을 일원적으로 규율하고 있는 점에서 주요 외국의 개정 민법보다 적극적으로 국제거래규범과 조화되는 타당한 입법이다. 다만, 추완청구권은 이행청구권의 연장이면서 불완전이행의 효과로서의 성격을 겸유하는 바, 채무불이행의 효과로서 강제이행청구권과 성격을 같이 하므로 제389조의2로 규정하는 것이 보다 적절할 것이다. 불완전이행의 경우 급부존속을 위한 채권자의 효과적인 구제수단으로서 대금감액권과 관련해, PICC를 제외한 국제거래규범들은 대금감액권을 채권자의 일반적인 구제수단으로 인정하고 있으며, 독일과 일본은 담보책임으로 이를 명시하였고, 프랑스는 계약불이행에 대한 일반적인 구제수단으로 신설하면서 종래와 같이 담보책임에서도 규정하고 있다. 대금감액권은 로마법상 하자담보책임의 본질적 내용임에도 우리 민법의 전신인 일본민법이 감액대금 산정곤란을 이유로 인정하지 않은 것은 법률의 흠결로 볼 수 있는데, 대금감액권을 규정한 민법 제574조의 실질이 하자담보책임이고, 감정평가 기술의 발전으로 산정곤란은 더 이상 장애가 되지 않으며, 도급계약 등 거래실제에서 감액청구를 보편적으로 활용하고 있기 때문이다. 나아가 매매대금 결정의 기초인 하자 없는 급부는 물건과 권리의 하자를 막론하고 요구되며, 대금조정에 의한 급부유지의 필요 역시 여행주최자의 담보책임·임차물의 일부멸실시 임차인의 차임감액청구권을 유추할 때 원시적·후발적 하자를 불문하고 인정되므로, 대금감액권은 계약책임의 일반적인 내용으로 인정될 수 있다. 대금감액권은 손해배상청구권과 기능·산정방법·산정시점·면책가능성의 차이가 있고, 일부해제권·부당이득반환청구권·상계권은 대금감액권이 갖는 효과의 일면만을 파악한 것으로, 대금감액권은 유상계약의 주관적 등가성을 기초로 하는 계약관계의 조정권이면서 불완전이행에 고유한 효과로서 형성권으로 파악될 수 있다. 대금감액권은 이행이익이 존속하는 한 대(大)는 소(小)를 포함한다는 원칙 등 다양한 근거에 의해 계약책임의 일반적 내용으로 인정될 수 있고, 그 법적 성격에 비춰 일부해제와 같은 효과를 발생시키는 면에서 민법 제544조를 근거로 인정될 수 있다. 대금감액권은 가분성이 없는 급부의 질적 하자·권리의 하자·하는 급부의 하자·후발적 하자에 대해서도 인정될 수 있고, 유책사유를 요하지 않지만, 이행지체와의 형평상 추완이행의 최고를 요한다. 감액대금은 약정대금을 실제가치에 대한 가정적 가치의 비율로 곱하여 산정하되, 현실적 급부가치를 평가할 수 있는 이행시를 기준으로 필요한 경우 감정평가에 의하도록 하는 것이 타당하다. 대금감액권의 행사를 위해서, 명문의 근거없이 하자통지의무를 요구하는 것은 부적절하지만 하자담보책임에서 매수인의 무과실요건은 관행화된 검사의무 이행여부로 판단되고 추완이행의 최고로서 하자통지의무에 갈음할 수 있다. 비금전채무의 급부감축권도 유상계약의 등가관계·계약유지의 원칙에 비춰 비금전채무의 분할가능성, 추완이행의 최고를 요건으로 교환계약 기타 일정한 유상계약에서 인정될 수 있다. 추완이행의 최고를 요건으로 하여 추완청구권을 사실상 우선하되, 신뢰손해와는 선택적으로, 확대손해와는 중첩적으로 행사할 수 있지만, 계약해제권은 채무자의 추완이행 거절·계약의 목적달성 불능의 경우 최종적으로 행사될 수 있다. 2013년 민법개정시안은 대금감액권을 담보책임의 내용으로만 명시한 데 반해, 대금감액권은 유상계약상 불완전이행의 특유한 구제수단으로서 원시적 하자여부와 관계없이 인정되는 것이 타당하므로 제544조의2로 규정하는 것이 적절하다.

1. Themodernization of the contractual liabilityhas been deemed as the common discipline and aim set forth in the norms of international contract law such as CISG, PICC, PECL, DCFR, and other recent revisions to the civil code from Germany, France, and Japan. In order to attain the aforementioned modernization process in the context of Korean Civil Code, this thesis would apply statutory interpretation and legislation theories to examine the following: (1) the possibility for the unification of defective performance liability law for harmonizing the structure of contractual liability, and (2) the expansion of the applicability of theright to completion of performance and theright to reduce price, which are narrowly stipulated under the liability of separate contracts in the Civil Code. 2. The Civil Code of Korea retains a binary structure for contract liability by stipulatingresponsibility for non-performance (of the obligation) based on the liability with fault, and on the other hand, responsibility for warrantyoriginating from no-fault liability. This twofold structure is open to overlapping liability and induced complications in statutory interpretation. In hindsight, this structure could be said to regulate defective performance liabilitycaused by defective performance or performance with defect. The pertinent international trade business law norms and major civil code amendments tend to unify contractual liability under a more comprehensive concept, while gradually dividing liability with fault from the contractual liability, unlike that of the tort liability. As such, regarding the responsibility for non-performance of obligations, the Article 390 of the Civil Code of Korea states a general provision specifying the requirement without particular reference to the reason for responsibility, whereas it only stipulates the substance on damages requiring the reason for responsibility. The other means of remedy comprise of the substance of the responsibility for non-perfomance, under other separate provisions and interpretations. Henceforth, against the backdrop of such tendency, this study has compared objective requirements such asdefective performanceand defect, and analyzed their divisibility with the subjective requirements such as damages, as part of the responsibility for non-performance of obligation arising from the reason for responsibility, through the lens of legal history, comparative legal approach and theory of law, in order to discuss the unification of defective performance liability into Korean Civil Code. Through the aforementioned methodology, this piece of dissertation proposes that there is no fundamental difference between the responsibility for non-performance due to defective performance and the liability for warranty due to defect, since both concepts are mutually approachable. Accordingly, there is a dire need for establishing new justification for attributing the contractual liability to the obligor, ultimately providing performance guarantee. Yet, considering the possible clash with the systematic interpretation among other provisions in the Civil Code, especially on the part of liability with fault, the mentioned suggestion should proceed with the legislation analysis method. In this respect, the concept of intention and negligence stated in Article 390 would be construed as a functional reason for remission of damages. A general provision on a rescission of a contract without element of remission formulated under Article 544 of the amended bill of Civil Code of 2013 could be evaluated as a leap forward in this regard. 3. In the case of defective performance liability, the right to completion of performance has been discussed as an effective means of remedy for realizing the performance for the obligee. The international trade business law norms recognized the right to completion of performance as a general means of remedy for the obligee. Germany and Japan have adopted such concept while not distinguishing the right as a liability for warranty and defect of goods. The amendment of an individual contract in France is still a ongoing process, but it is expected that they would also be able to ascertain the right to completion of performance based on the new inclusion of enforced actual performance as a means of remedy for the non-performance of the contract. In terms of Korean Civil Code, the right to completion of performance would be able to solidify its ground for justification as a responsibility for non-performance and liability for warranty, based on numerous claims- ranging froma contractually binding supplementary means for the right to demand performance, and simulteneously, to a principle, accrued to the effect from defective performance that differs from restitution, postulating that as long as the expectation interest/performance interest is realizable, the macro concepts could encompass the micro concepts and more. Based on the legal nature of the suggestion above, it would be highly appropriate to link the positive law basis, by referring to the provisions on compulsory perfomance of obligation stipulated in Article 389, as means of remedy of non-performance of obligations. More specified categories of the right to completion of perfomance could include right to require delivery of substitute goods, right to demand performance in respect to the missing or non-conforming portion of the performance, and right to require repair. The delivery of the goods of non-conforming description with the contract would invoke the effect of defective performance and thus be regulated by the right to require substitute performance. Other cases involving the applicability of right to completion of performance should be determined along with a possibility for cure for each case. For the sake of exercising the right to completion of performance, buyers no-fault requirement in the context of liability for warranty against defect could be judged by considering whether the buyer was heedful of the examination obligation, which is quite a customary procedure. Yet it would be inappropriate to demand obligation to notice defect without codified reference. In principle, the obligee may choose the type of cure, but when applying a systematic interpretation, such right should be exercised within a specified reasonable period of time. In addition, a concurrent performance relationship between sellers obligation to require non-defective goods and buyers obligation to return the goods could be formulated, and prior to the demand of non-defective goods, the buyers benefit of use is within the scope of the contract, so it cannot be seen as an unjust enrichment. As an expansion of demand for performance, the right to completion of performance could be limited in accordance with the good faith if there exists a situation where reciprocity is not met. For instance, when a performance is impossible or when a demand itself imposes excessive burden to the obligor. To add on, approving the right to cure to the obligor who contributed to the formation of the liability without invoking a codified provision would be seen as an unreasonable measure, especially when taking into account its legal nature. Reflecting on the legally binding force of the contract, in principle, it seems reasonable to priotize right to completion of performance by allowing peremptory notice to perform cure for a reasonable period of time before exercising right to claim for damages and right to rescind contract. Yet, when abiding by the text, it would be advisable to interpret that the buyer would have the choice between the right to claim for damages and the right to completion of performance as a corollary of liability for warranty. The impossibility of achieving the object of the contract, which is a requirement for the right to rescind the contract, should be interpreted in a rigorous manner, under a premise of impossibility of cure. The amended bill of Civil Code of 2013 is exceptionally appropriate legislation, which could be harmonized with the international trade business law norms, and moreover, it could be evaluated as a more proactive amendment compared to other foreign amendments in that the right to completion of performance has been specified as not only responsibility for non-performance but also as a liability for warranty. Furthermore, the content and limitation requirements of the right to completion of performance corresponding to the responsibility for non-performance are coherently regulated. However, the right to completion of performance is an elongation of right to demand performance and simultaneously, it is also an effect of a defective performance. Henceforth, it would be desirable to stipulate this notion as Article 389-2, considering its nature as a claim for a compulsory performance of obligation, effectuated by non-performance of the obligation. 4. As for the defective performance, as far as pursuing an effective means of remedy for the obligee for duration of the performance, the majority of international trade business law norms, with an exception of PICC, recognize right to reduce price as obligees general means of remedy. The civil codes in Germany and Japan have explicit mention of the right to reduce price under liability for warranty, and the civil law in France has included it under a general means of remedy for the non-performance of the contract while maintaining its place in liability for warranty section. The right to reduce obligation, although it is one of the fundamental issue of the liability for warranty against defect in Roman law, has not been authorized under Japanese civil law due to the complexity entailed in calculating the price to be reduced. The Korean Civil Code followed suit but this would be a legal lacunae since the Article 574, stating the right to reduce prices fundamental context, is accrued to liability for warranty against defect, and the difficulty in calculation has been abated due to the development in assessment technology. In reality, the request for reducing price is utilized comprehensively in actual cases of contracts, such as that of the contract for work. Furthermore, the performance without defect, as a basis for decisions regarding purchase-price of the sale, is required no matter whether there exists any defect in the goods or rights. The necessity for the maintenance of performance by adjustment of purchase price is required regardless of any initial or subsequent defect when inferring right to demand reduction the rent from the invocation of liability for warranty by a package tour organizer or from the case of partial loss of object leased by a lessee. The right to reduce price is distinctive from that of the right to claim for damage in its function, estimation method, time of the estimation, and possibility for discharge. The right to partial rescission, the right to demand for return of the unjust enrichment, the right to set-off account for only some parts of the effect that the right to reduce price can be entitled with. Consequently, the right to reduce price is, on one hand, a right to adjustment for the contractual relationship based on subjective reciprocity of a contract for value, and at the same time, on the other hand, it could imply a right to unilaterally alter legal relationship arising from a defective performance. The right to reduce price could be included in the general context of the contractual liability, based on a wide spectrum of reasonings, recalling the principle illustrating that as long as the expectation interest/performance interest is realizable, the macro concepts could encompass the micro concepts in this regard. The mentioned right could also be invoked under the Civil Code Article 544, since its legal nature gives rise to an effect similar to that of the partial recission. The right to reduce price can be applied for numerous defects, ranging from qualitative defect of indivisible performance, defect of right, defect in the performance of obligation to implement the means necessary to obtain certain result (obligation de moyens), and even to subsequent defect. The right to reduce price does not obligate cause for which the obligee is responsible but it would necessitate a peremptory notice of cure of performance taking into account the equitable treatment among the performing entities. The reduced purchase-price would be calculated by multiplying the rate or proportion of estimated value to the agreed purchase-price. The time period of such computation should be set at the time of the performance since it is when the actual value of the performance could be accurately evaluated, and when necessary, it is reasonable to let an assessment evaluation process to take the initiative. For exercising the right to reduce price, it would be quite inappropriate to demand an obligation to notice defect without a written reference, but one can assert that the requirements under the buyers liability without fault in pursuing liability for warranty against defect could be determined by whether an obligation to examine has been performed, and such requirements can substitute the obligation to notice defect in a form of peremptory notice on performing the cure. Directed by the equivalence of the contracts for value and the principle of maintenance of the contract, the non-monetary obligations right to reduce obligation could be substantialized under contract of exchange and other forms of contracts for value, under the condition of divisibility of the non-monetary obligation and peremptory notice on the performing the cure. By specifying the requirement on the peremptory notice on the performance of the cure, one can in fact give more weight to the right to completion of performance. This could be exercised selectively with damages for reliance interest, and interchangeably with damages for consequential damage. However, one will be entitled to the right to rescind the contract when the obligor refuses to perform the cure and when there is impossibility for achieving the object of the contract. Even though the amended bill of Civil Code of 2013 has only stipulated the right to reduce price in the context of the liability for warranty, this thesis posits to specify the right to reduce price as a means of remedy for the defective performance in contracts for value, regardless of the existence of the initial defect, and correspondingly, concludes that a new provision of Article 544-2 of the Civil Code should be supplemented based on the underlying rationale.