As @Denti says it's mostly contained in a written contract with the union which is published in german only and won't be easy to read for those unfamiliar with the language.
Additionally and especially for L/R ops there might be further reglulations concerning crew complement, rest times enroute and at the homebase that are negotiated within the company (i.e. not with the union) and established for each flight plan period an not normally published in written.
Are you interested in any special aspect in depth or more in the regulations in general?
RGDS, max