The Concept of Non-Contractual Obligations

condictiones
have replaced the contractual 
restitutio in integrum
as the central means of 
unwinding contracts, that they are conceived of as non-contractual claims for unjustified enrichment, 
and from the fact that the different instruments unwinding a contract are discussed independently of 
each other. 
Similar problems can also be seen in French law. Here, the Roman 
condictio indebiti
(
répétition de 
l’indu
) is also used for unwinding void contracts. On the one hand, the traditional prerequisite of this 
action, the error of the performing party, has been found inadequate for these cases: Cass Ass plén (2 
April 1993) 

1993

Recueil Dalloz Sirey 373, 375. On the other hand, the Cour de cassation has 
early made each party bear the risk of what it had received under the contract: Cass civ (13 May 
1833) 

1833

Sirey prem part, cols 668 ff). Yet this was difficult to reconcile with the principle that 
the risk pertains to the owner (
res perit domino
). As the transfer under a void contract has no effect 
under French law, the Cour de cassation later reversed this decision and assigned the risk to the 
performing party: Cass 1st civ (6 December 1967) 

1967

Bull civ I, No 358. This was convincing in 
the specific case, where infected animals had died when they were in the buyer‟s possession. Yet 
such a result is less convincing if the object of the contract is consumed before the nullity of the 
contract becomes apparent. Neither this general principle of the law, nor the wording of the 
provisions on the 
répétition de l’indu
allows the question of risk-assignment to be addressed 
adequately.
 
61
See fn 76. 
62
Wendehorst
(fn 45) 68–83, 96. 
63
See 
Zimmermann
(1995) 15 OJLS 407: „Why there was no legal ground for this specific transfer is 
entirely irrelevant. The underlying contract … may not have come into existence; it may have been 
invalid for a whole variety of reasons; it may have concerned another object of performance; or it 
may have related to a different creditor. All this has to be determined according to the law of 
contract. The law of restitution does not have to concern itself with these issues‟. Cf also 
JP Dawson
, Retreat from Contract as a Recourse after Breach, in: Festschrift für Konrad Zweigert 
(1981) 417, 430: „… an extension from – “rooted” in – contract and only in slight degree dependent 
on the law of restitution‟. 
64
But see 
Hellwege
(fn 58) 425–451: during much of the history of European private law, contracts 
were unwound by a wide range of different actions or institutes. Yet, all these instruments had the 
same legal consequences, because they were seen as different forms of an abstract idea of 
restitutio 
in integrum
. 

---

13 
damages. In this respect, it may be decisive whether the contract was void 
ex tunc
or only for the future. Yet such divergent results are rarely based on convincing 
normative considerations; normally, they can only be explained as the result of 
historical or doctrinal accident. Indeed, the decisions whether a contract is held void 
ex nunc
or 
ex tunc
, and whether a contract is void or will only be reversed, are 
mostly of a merely technical nature. Often, such decisions were motivated by 
considerations that had little to do with the correct assignment of risks.
65
Thus, 
courts wanted to ensure arbitration clauses or limitations of liability remaining 
effective even if a contract was reversed
66
or they wished to grant contractual 
claims for damages despite the fact that the contract was unwound.
67
All this shows 
that the borderlines between contractual instruments, such as termination for breach 
of contract, a right to rescind a contract due to mistake, misrepresentation, or duress 
on the one hand, and non-contractual remedies in the case of the absolute nullity of 
contracts violating the