Your employment contract should say if and when you need to ask your employer. Aside from that, you also need to worry about Arbeitnehmererfindungsgesetz: https

Your employment contract should say if and when you need to ask your employer. Aside from that, you also need to worry about Arbeitnehmererfindungsgesetz: https://www.gesetze-im-internet.de/arbnerfg/ https://www.gesetze-im-internet.de/arbnerfg/ Especially if you intend to make money off of it.