FRANKFURT (Reuters) - Deutsche Bank has made a settlement offer with shareholders who had sued Germany's largest bank for underpaying them for the acquisition of Postbank, a plaintiff's lawyer said on Friday.

The lawyer, Jan Bayer, rejected the proposal as a "crackhead" offer.

Deutsche Bank said it would not comment on the talks.

"As we’ve stated in the past, we are in settlement discussions with various groups of plaintiffs within the several Postbank takeover proceedings," Deutsche Bank said in a statement. 

(Reporting by Tom Sims, Editing by Elisa Martinuzzi, Rachel More and Miranda Murray)