Those are small trailers that you can pull with small cars in the US. The US has many RVs that need much larger trucks to pull them as well. I don't have much autobahn experience, but I don't recall ever seeing a RV type trailer like are somewhat common in the US.

Even if your car can pull the trailer, that doesn't mean you should. If the trailer is oversized the car and engine can pull it - but you need something much bigger/heaver to control the load if anything goes wrong. More than one person has had their car roll because they were towing a large trailer at high speed and a wind gust pushed them into the ditch. If they were towing at city street speeds they would have been okay, but not autobahn speeds.

You don't need a 7.5 tonner to pull a small trailer. However you do need to carefully check the tow rating, bad things happen if the tow vehicle is too small. You do need a 7.5 tonner to pull a large trailer though.