(c)  German law

be transferred by the obligee to another person by contract with that person’, adding that the transfer takes effect at the point at which the contract of assignment is entered into. Such a contract of transfer is separate to any preceding contract for the assignment which may precede the latter contract of transfer. The contract of transfer however merely affects the position of the assignor and assignee inter se: until the debtor receives notification of the assignment, he remains free to tender performance to the assignor.117 In other words, intimation of the assignment to the debtor is required to bring the assignee and debtor in to a formal relationship. Assignment may be prohibited by the parties in their contract.118

There is separate provision in the BGB for the transfer of duties, which again requires to be achieved under a contract,119 as well as a further provision stipulating that any such transfer requires the ratification of the party to whom the debt is due before the transfer becomes effective.120

(d)  Model law

In the DCFR, the general rule is that all rights to performance are assignable unless otherwise provided by law.121 Substitution of debtors is treated separately.122 The general rule on assignment is worked out in a quite radical way through the further provision that a contractual prohibition or restriction on assignment does not prevent such assignment.123 This puts the DCFR position at odds with the position in a number of national systems that the parties are free to prohibit assignment if they so stipulate in their contract and that such a prohibition is effective to prevent an assignment. The DCFR position may be argued to undermine the right of a promisor to determine the nature of the promise undertaken by it, in that it restricts the promisor’s right to determine to whom the promise is to be performed. A sop to the freedom of the promisor to determine the nature of the right promised is offered by way of the fact that ‘personal rights’ may not be assigned unless with the permission of the creditor,

117 §407(1) BGB. 118 §399 BGB. 119 §414 BGB. 120 §415 BGB.

121Art. III.-5:105(1). The applicability of the regime on assignment only to rights of performance is somewhat limiting. For instance, in a case where A lets property to B, and B then sublets the property to C, a right in the lease between A and B entitling B to trigger arbitration in relation to a matter (such as whether the property is in need of repair by A) by an agreed arbiter would appear not to be able to be assigned to C, even if it might be C who has a direct interest in such an arbitration, because such a right is not to a ‘right to performance’ by A.