Here are some sites where you can start your search for CC-licensed free music for videos. Each site contains a mixture of licenses, so check each track before using it in your video.
Learn about audio copyright and where you can find creative commons music for video.
Online-Quellen zum Download freier, kostenloser oder GEMA-freier Musik, Sounds und Geräuschen zur Nachvertonung von Videos, Podcasts und Hörspielen