The French tradeships are supposed to get 20% extra ressources however they are getting more. The videos below show the ressources gathered by an English (I also tested with Delhi to be sure it is not an English bug) tradeship and a French one on the same trading route (same dock location on exactly the same map).
As you can see the English ship got 33 G 33 W while the French one got 44G 44W this seems to be 33.33% bonus not 20% (in another test with slightly different dock location before I decided to record it was 32 vs 43 which is 34.3 extra but this could be a rounding issue).
For reference the map seed used in videos on Baltic micro size Mediterranean Biome with seed: 1b11111d
I also tested on Boulder Bay (same paremeters but seed 1b11111f) and got 55 vs 74 so 34.5% extra ressources. (See screenshots Below).
Edit: The seeds are obviously irrelevant as there is no map issues involved, I was only testing for the sake of testing and discovered the bug then chose random fixed seeds just to reproduce and post the bug report to make things easier.