Please note the following:
Publishing Open Access is not free of charge for authors. Do your research on where you want to publish and what the costs will be when you submit your application.
Check the funding agency's guidelines or the call for proposals to determine whether fees for OA publications are eligible and include them in your project calculation, if applicable.
For DFG applications, lump sum publication funds between €750-5000 per funding year can be requested. These funds can also be used for open access publications.
The BMBF offers the possibility to apply for Open Access funding for already completed projects.