German all the way..
One quick was is to ID the Scroll and Gears to see if they are original to the Bass. if so, then one thing to remember is the the French NEVER used German Gears.
Also, the Neck/Scroll looks to be Beech and not Maple. Every French Bass I have seen in original form has had Maple neck/Scroll and some form of French Gears.
Also, if the Bass has outer linings (which this does not) then it will not be French either.
If the Bass has Purfling that goes around wither the Top and or Back plates, then that too is not 100% French in making. Many quasi Cello models were made in France but the Germans did this as well.
Here are two examples Top and Back each. Please try and guess which is German and which is French. Try from the Tops first as the Backs look more obvious, or at least to my eye they do.
FYI, it doesn't matter if it's a Round Back or a Flat Back as both were made in either country.
On the German Bass above, note that there were many grades of instruments produced from total handmade down to Blockless factory models in the late 19th to early 20th century but mostly factory grade by the numbers. I see just about every other well made German bass attributed to French origin but erroneously. This is most often done by the dealers selling them no doubt and had passed down false teachings as to what the differences are between French work and German work and believe me, there is good and not so good in both schools.