The common license in France allows only 3.5t.
My van is 1.81t, empty, load allowed 1.2t. So it is registred at 3.01t. The trailer accepted with no question is 0.5t. Even with this small trailer, in theory I'm already out by 10 kg.
My tiny 4" chipper weights 0.4t. Loaded with it, my trailer reaches 0.51 t. Too much by 10 kg too, but I can live with that.
Next level : 4.25t, it's simplified and should be easy to get. In my case, I could have a trailer of 1.24t. As this one weights around 0.3t at least, that gives a load of less than 1t. Too bad, the miniloader I really wanted to buy is a tad over 1 t. So overloaded again. I have to get a smaller one, a bit light for the job at 0.7t, but I don't want to go to the real exam needed to obtain the next license's level ("trailer license", for a trailer up to 3.5t).
It's already an headache, just trying to memorise the details !