The Concept of Non-Contractual Obligations

ordre public
or made by minors on the other hand, are often 
blurred or arbitrarily drawn.
68
In such situations contractual remedies and non-
contractual claims for unjustified enrichment are closely related with one another. 
Differences between such remedies therefore tend to create a desire, not necessarily 
for absolutely uniform rules, but for doctrinal adaptation and normative coherence. 
Yet, as there is hardly one single obviously right answer to the questions of fair 
assignment of risk, doctrinal controversy is an almost unavoidable consequence.
69
This cannot only be seen in English common law, which provides for a wide range 
of instruments to unwind contracts,
70
but also in Italian
71
and German law,
72
65
R Zimmermann
, Restitutio in integrum: The Unwinding of Failed Contracts under the Principles of 
European Contract Law, the UNIDROIT Principles and the Avant-projet d‟un Code Européen des 
Contrats 

2005

Uniform Law Review/Revue de Droit Uniforme 719–735, 728 f. 
66
See the comparative remarks in Note 3 to Art 9:309 PECL. Indeed, these remarks altogether show 
that the doctrinal question whether termination has retroactive or prospective effect is of no 
significant relevance for the fair assignment of risks. 
67
Thus, under German law, a rescission (
Rücktritt
), which originally nullified the contract 
ex tunc
, is 
today 
assumed 
to 
transform 
the 
contract 
into 
a 
mutual 
obligation 
of 
reversal 
(
Rückgewährschuldverhältnis
). This shift in doctrine was motivated by the only reason that 
rescission not exclude contractual claims for damages; see 
H Stoll
, Rücktritt und Schadensersatz 
(1929) 131 AcP 141–185, 146 ff, 171 f. 
68
Di Majo

1994

Rivista Critica del Diritto Privato 323 ff. 
69
Hellwege
(fn 58) passim; 
Zimmermann

2005

Uniform Law Review/Revue de Droit Uniforme 
727 ff, 731 ff and passim. 
70
A complete overview can be found in 
Hellwege
(fn 58) 199–227 (rescission for mistake), 236–252 
(failure of consideration; nullity of contract for want of legal form, juridical incapacity, error, and 
illegality), 254–268 (frustration), 274–278 (repudiation of the contract), 280–286 (withdrawal). 
71
See for an instructive picture of the present debates 
Schlechtriem 
(fn 3) vol I, 455–468, with 
further references.
72
Thus, a buyer who was cheated by a seller may challenge the contract because of the seller‟s fraud. 
The contract is then regarded as void from the outset, so that the 
condictio indebiti
will be applied 
(§§ 123 (1), 142 (1), 812 (1) 1, alt 1 BGB). Alternatively, the buyer may rescind from the contract 
because of the defect (§§ 437 no 2, 440, 323 BGB). Yet, these provisions may lead to a different 
assignment of risk if the buyer grossly negligently destroyed the object of sale: whereas the buyer 
has to compensate the seller under (§§ 437 no 2, 346 (2) no 3, (3) no 3 BGB), there is no such duty if 
the buyer avoided the contract for fraud, because in this case the 
Saldotheorie
would not be applied 
(see below fn 78). On the other hand, though, he would not be entitled to a contractual claim for 
damages in this case (§§ 280 ff BGB) because a void contract cannot give rise to contractual claims. 
All this may be obvious for the lawyer, yet it is difficult to understand for the layman, who simply 
wants to unwind the contract. 

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14 
although under present German law „only‟ one contractual (