You might think 1939 is not relevant anymore, how about 1994 obligations? https://en.wikipedia.org/wiki/Budapest_Memorandum_on_Securit...
In theory France was supposed to intervene in Ukraine in case of Russian aggression, in theory.
There will be ZERO reaction when (not if) Russia invades Estonia. Remember Russian invasion of Georgia in 2008? Guess who was the ONLY one actually doing more than public statements from the comfort of their own office(and note that some like Merkel didnt even criticize Russian aggression)? Polish president flew over warzone (Russian controlled air with active military aircraft around) to join Georgian parliament in protest. Guess where is Polish president Kaczynski now - died mysteriously in plane accident over Russian airspace two years later.
Outside of France I fear it's mostly paper tigers, even the UK. France is clearly one of the most militaristic nations in Europe and the only one who has demonstrated willingness to use force (see UK's parliament report on the Lybian intervention).
I still think Russia is a lot stronger than people think.