Germany is a great country for hitchhiking. Just make sure you get on the Autobahn (motorway)! There it is best to get to a Raststätte (service area) where drivers can legally stop and get from one to another. You will often find maps with the motorways and the service areas along them.
In Germany there are no speed limits on many highways. So you might first want to try to get a ride with fast cars before asking truck drivers! Trucks are great during nighttime, but like in France, there are restrictions to when they might drive. In Germany, trucks aren't allowed to drive on weekends from Friday 12 PM to Sunday 10 PM or on public holidays.
In Germany license plates start with an abbreviation of the region where the car is registered. So look out for number plates starting with B if you're hitching to Berlin!
- See German car number plates and List of abbreviations used (in German) on Wikipedia for more information.
Germany implemented the Schengen Agreement. This means, that the border to other Schengen countries are open. At the borders to non-Schengen countries (Poland, Czech Republic and Switzerland) there are still checkpoints and German custom officers or sometimes police might control your luggage, especially if you come from eastern european countries like Poland (searching for forged branded goods, smuggled tobacco, etc.), or if you come from or cross over into Switzerland (black money is often smuggled over that border). If coming in with a commuter train, they easily take you out of your train to search your belongings, while your train continues without you.