1 - Dortmund Essen you may write and ask for birht - death - mariage ceertificate usually they ask you to pay 4 euro / stron
2 - in France you may write to the Mairie Hall town , to get birht death and mariage certificate usually it s for free you should say it s for your Genealogie
3 - You may ask for documents in Coal mine company but it may takes a lot of time need auth.. etc. there you may get some info about his work in mines.
(for france I can help to translate I m french)
I can help ,