Inclusion of Ts&Cs
German law requires that the Ts&Cs must be agreed on in order to have them validly included.
The agreement can be express, e.g. in a framework agreement, but also implied. The implied inclusion requires a noticeable reference to one’s Ts&Cs. In particular, it is necessary to unambiguously name the Ts&Cs to which reference is made.
A reference to one’s Ts&Cs on offer documents and/or order documents is sufficient (unless there is a Battle of Forms situation).
Whether a reference on a confirmation document is sufficient, is somewhat unclear under German law. The majority of case-law and legal commentators seem to advocate that such reference is sufficient.
A reference on shipment documents or invoices is generally not sufficient for a valid inclusion of Ts&Cs.
It is not necessary to include the Ts&Cs‘ actual wording. It is sufficient if in either of the above-described documents reference is made to a homepage or if it is stated that the Ts&Cs will be sent upon request.
From a German law perspective, under the CISG, the situation equals the situation described for national law.
However, there is one major difference when it comes to the question whether Ts&Cs only must be referred to or whether their actual wording must be provided. The German Federal Court of Justice has ruled that Ts&Cs must be actually sent to the other party in order to have them validly included. The mere reference to a homepage or any comparable statement is not sufficient under the CISG.
Battle of Forms
Under German law, the Knock-Out Rule applies.
From a German law perspective, under the CISG, the majority of legal commentators supports the Knock-Out Rule. Furthermore, a decision by the German Federal Court of Justice, which was rendered in 2002, seems to support the Knock-Out Rule.