It is one of the Catalpas, also called Indian bean trees.
There are about five species/hybrids grown in the UK, probably the same in France.
Yours is probably the southern catalpa, C. bignonioides - the most common one.
However, C. speciosa is also a possibility. The best way to distinguish between these two species is the width of the seed pods: 6-8mm wide in C. bignonioides; 1.5cm wide in C. speciosa. If your tree has pods, eg. from last year, you might check that...
I'm having thoughts about this as there are two trees, both well over four years old and each is quite small and with a straight trunk and mushroom-shape. The canopy is a perfect curve. Most of the images I have seen of Catalpus.are large, rather straggly trees.
Quite right to have second thoughts.
I should have done so myself, but I was relying on my copy of 'Mitchell', which is missing some species.
It looks like you have Catalpa bungei, which goes by such common names as dwarf Indian bean tree and umbrella tree.
Catalpa bungei is an accepted name.
But it is not clear to me if you have the species or a cultivar of it, or actually a cultivar of a different species. The issue is confused by published names such as Catalpa bignonioides (Catalpa bungei) "NANA"
It is also possible that you have a cultivar grafted onto a standard trunk of a different species.