Customs question

Assuming that your luggage is checked through, immigration/passport control will be in Germany and customs in France. If they're not checked through, the whole deal will be in Germany.

Just to add to the previous response, you are really concerned about two different procedures, Immigration, in your case into the Schengen area (as opposed to the euro zone) and Customs, which basically is the Euro zone in this case, but handled by your destination country. So as was mentioned, you will go through immigration in Germany and customs in France, though to be honest, customs is rarely a "process", in most countries, as you exit the secure area there will be a sign, indicating that if you have nothing to , simply exit, if you do, then go talk to the people at the customs desk. It is your choice, though they have they authority to pull people aside. Once you are inside the Schengen area, then No, you do not need to go through any immigration or passport checks when crossing borders as long as you stay in the Schengen area, though again, each country has the authority to do checks. For reference, the Schengen area includes most European countries, with the UK, Ireland, and some Eastern European countries being the notable exceptions.