I did some further digging around on this issue on my own.
I created a fresh profile of ProMods without the TCP installed and the skins for the France DLC companies were available again in the Trailer Browser for the Curtain Side and Platform trailers.
It appears something is not quite right with the Replacment version of the TCP. With the Replacment version installed, the skins for the France DLC companies are no longer available for the Curtain Side and Platform trailers, resulting in the use of the Default white trailer skin for these two trailer types. I unfortunately don't know enough about how the trailer skins are handled to even try to correct the problem.
For the cargoes that use the Curtain Side or Platform trailers, I'm currently picking the Schwarz Mueller DLC Curtain Side trailer when picking up trailers at the France DLC companies until this can be resolved properly.
EDIT:
I think I found what the actual problem is. For the Replacement version of the TCP, there are no definition files for the France DLC companies in the directory "\def\vehicle\trailer\promods_tcp\" for the trailer models being provided to replace the default SCS models. Since it can't find the required paint job files for the France DLC companies, it is certainly defaulting to the white default trailer skins.
EDIT 2:
Okay, I think I created a functioning patch for the Replacement version of ProMods TCP to restore the France DLC company paint jobs so they won't have white trailers anymore.
Here's the link to the patch that I uploaded myself to ShareMods:
promods-tcp-vlf-patch.zip - 25 KB.
Load this file just above the Replacement version file in the Mod Manager and it should restore the missing paint jobs for the France DLC companies.
NOTE: I did
not modify the existing ProMods TCP files in any way. I just simply provided the missing definitions for the paint jobs for the France DLC companies.
I guess I do know enough about how the trailer skins are handled after all to fix the issue. It just wasn't a quick thing to do as it took me about 1.5 hours to study the directory structures and test.