이 글에서는 장래채권양도 후 채무자와 채권자가 양도금지특약을 체결한 경우 장래채권양도의 효력을 검토하였다. 이 문제에 관해 법률상 공백이 존재하므로 법관의 법형성을 통해 해결할 수밖에 없다. 계약당사자의 계약내용 결정의 자유을 존중할 것인지, 채권이 처분 및 유통 대상인 점에 주목하여 채권의 유통성을 강화할 것인지는 정답이 없는 문제이다. 우리 민법에는 두 관점이 모두 담겨있다. 논리적, 법리적으로 옳은 한 개의 정답이 없다면 다양한 형량토픽을 종합적·귀납적으로 고려해 -100% 만족스럽진 않더라도- 더 나은 답을 찾을 수밖에 없다(문제변증론). 실정법 차원, 법원리 또는 정책적 차원, 비교법 차원의 형량토픽을 고려할 때, 장래채권양도시점에서 양수인이 장차 채권양도금지특약이 체결될 것임을 충분히 예상할 수 있었던 경우가 아닌 한 채권양도는 유효다고 봄이 타당하다. 이러한 예외적 사정은 채권양도가 무효임을 주장하는 채무자 측에서 증명해야 한다.
입법론으로는 상행위로 발생한 금전채권을 양도하는 경우 양도금지특약에 반하는 채권양도라도 절대적 유효로 보고, 그 외의 채권양도는 민법 제449조 제2항을 유지하여 양수인이 선의·무중과실이 아닌 한 절대적 무효로 봄이 타당하다. 전자의 경우 장래채권양도 후 채무자와 채권자가 양도금지특약을 체결하더라도 채권양도는 항상 유효이다. 후자의 경우 장래채권양도 후 채무자와 채권자가 양도금지특약을 체결한 경우 채권양도는 절대적 무효로 봄이 타당하다. 절대적 유효 영역을 인정함으로써 현실거래에서 장래채권의 유통성 확보에 별다른 문제가 없게 되었다면, 절대적 무효설 영역에서는 계약자유 원칙을 강조함이 바람직하기 때문이다.
In this article, the author examines if the assignment of future claims is effective when the debtor and the creditor enter into a non-assignment agreement after the creditor(assignor) and the assignee have assigned the future claims. There is a gap in the written-law regarding this issue. Therefore, judges who cannot refuse to decide for a lack of applicable norms, have no choice but to resolve it through their own law-making. At the heart of this issue, there are two opposing ideas; whether to respect the freedom of the contracting parties (the debtor and the creditor) to determine the contents of the contract, under the premise that the non-assignability of receivables is a kind of the contents of their contract, or to improve the assignability of receivables by focusing on the aspect that receivables are objects of disposal and trade. However, there exists no single right answer in a logical, doctrinal sense as to which idea is correct. The Korean Civil Code contains both perspectives. In this situation, we should seek a more practical solution, even if it is not entirely satisfactory, by considering various balancing topics on a comprehensive and inductive basis (topic theory). In considering the balancing topics in written-law, legal principles or policy, and comparative law, the following conclusion is desirable; the assignment of future claims is effective unless the transferee, at the time of transfer of future claims, could clearly anticipate that a non-assignment agreement would be concluded in the future. Such foreseeability must be proven by the debtor who claims that the transfer of future claim is invalid.
In terms of legislation, the author suggests a two-tier approach (absolute validity + absolute nullity); with monetary claims arising from commercial trade, the assignment of receivables is valid irrespective of a non-assignment clause and regardless of an assignee’s knowledge of a non-assignment clause (absolute validity). With other claims, the current system under Article 449, Paragraph 2 of the Korean Civil Code is maintained. An anti-assignment agreement between creditor and debtor provides an absolute effect not only between them but also with others, especially assignees (absolute nullity), except when an assignee, without gross negligence, is unaware of the anti-assignment agreement. In the former case (absolute validity), the assignment of future receivables is also absolutely effective, even if the debtor and the creditor enter into an anti-assignment agreement after the transfer of future receivables. In the latter case (absolute nullity), it seems desirable that the assignment of future receivables always becomes absolutely invalid, when the debtor and the creditor enter into an anti-assignment agreement after the transfer of future receivables. In the area of absolute nullity, the principle of freedom of contract should be emphasized, because we have already strengthened the assignability of receivables and removed the hurdles in financial transactions by recognizing the area of absolute validity.