If that was true many more tankers would have passed from other countries that were more against the war.

France is one of few countries with large military presence in the area, that is the only thing they do more than most other countries.

Edit: And France even directly threatened to use force here. If you only read American news you wouldn't know since they want it to seem like the world is on Irans side here. What we are seeing is that Iran has started buckling to these threats, not that they are giving passage to those who didn't threaten.

> France is advising Bahrain on a draft United Nations Security Council resolution that would authorize the use of force to reopen the Strait of Hormuz and restore global energy flows, according to three diplomats informed of the process.

https://www.politico.eu/article/france-advising-bahrain-un-s...

France also joined China and Russia in blocking Bahreini resolution that would authorise "all defensive means necessary" to protect commercial shipping in the strait. That is why their tanker passed.

France also has a problem with Israel waging war in Lebanon, a former French administered teritory. As long as Israel sticks to eliminating Hezbollah only, they'll shut up about it, but anything beyond that, like that bridge bombing or displacing and killing civilians it's bound to have a negative reaction from France.