In its judgment of May 20, 2008 (9 AZR 382/07), the Ninth Senate of the BAG dealt with the effectiveness of a clause agreed on a formal basis.
The Senate maintained that in the case of a clause that not only prescribes the written form for changes to the contract, but also requires changes to the contract to be made in writing, this cannot generally be waived by an agreement that does not comply with the written form. Such a “double” written form clause can therefore prevent a company practice from occurring.
However, according to Section 305b of the German Civil Code (BGB), individual contractual agreements have priority over general terms and conditions. This principle of the priority of individual contractual agreements also prevails over effective constitutive written form clauses. This also applies to a double written form clause. A double written form clause, which is subject to the general terms and conditions control, is therefore due to the existence of an unreasonable disadvantage in accordance with. § 307 Abs. 1 Sentence 1 BGB is ineffective if it is worded in such a way that it gives the other part of the contract the impression that an oral agreement made after conclusion of the contract is ineffective contrary to Section 305b BGB.
The misleading nature of the legal situation in the overly broad clause can prevent the contractual partner from enforcing the rights to which he is entitled. The misleading written form clause is ineffective overall. It cannot be maintained for a company exercise because this in itself does not represent an individual contractual agreement within the meaning of Section 305b of the German Civil Code (BGB): This applies to general terms and conditions from Section 306 Para. 2 BGB derived ban on the validity-preserving reduction.