France among many nations called bullshit on the WMD claims, we threatened to veto the UN Security Council resolution authorizing a military intervention and we refused to get involved in that mess.

The fact that the US government decided to unilaterally invade Iraq anyway is not our responsibility to bear. What could France have done more, try and enact economic sanctions or wage war against the USA over this?

"What could France have done more"

Everything it is doing now towards Russia.

Giving weapons and ammo to Saddam Hussein?

Besides the logistical, economical and industrial challenge of supplying enough kit to even make a dent against the expeditionary forces of the USA, which were still doped sky-high on Cold War hand-me-downs, that sounds like a terrible idea.

Hussein's Iraq was not Zelensky's Ukraine and not just because of strategic reasons. The Gulf War happened because Hussein wasn't a friendly neighbor to Kuwait.

You are confusing the Gulf War, which was in defense of Kuwait, with the illegal invasion of Iraq in 2003 based on false pretenses.

"Giving weapons and ammo to Saddam Hussein?"

The US is giving weapons to Azov [0], Ukrainian neo-Nazi ultra-nationalists.

[0] https://en.wikipedia.org/wiki/Azov_Brigade

They did not participate?

That was very brave

Not very but look at the countries participating. Weaker or intertwined (UK)

"Weaker"

Poland, being Poland, was after Iraqi oil [0].

France kept doing business as usual with the US despite American illegal war.

[0] http://news.bbc.co.uk/2/hi/europe/3043330.stm

Yeah, so ? Did you expect France to fight the US ?

France is a nuclear power. But you are right, a vassal can't fight his suzerain.