Welcome to our community and thank you for sharing your situation.
The reason why Germany has asked you to leave is due to the Dublin III Regulations, which make the first country you arrived in and applied for asylum the responsible country for your case - that's France. The German authorities probably saw you had already received a rejection there and don't feel responsible. (More information on Dublin III: http://w2eu.info/dublin2.en.html)
You usually have the opportunity to appeal against the decision, but the deadline most likely passed a while ago.
Especially because you have two children, it seems to me that the best thing you can do in your situation is to speak to an expert about your case. If you are still in Germany, there are several centers who support asylum seekers, also offering free legal advice. Here's a website where you can search for pro bono legal advice in your area: http://www.refugeelegalaidinformation.org/germany-pro-bono-directory
Please let us know if you need further assistance. Good luck with everything.
All the best,