Україна Ukraine

At what point does a country assisting Ukraine become "at war" with Russia?

Obviously a country is free to send money to Ukraine. Countries send foreign aid all the time, often in the form of money.

And a country can sell weapons to other countries. So if you combine that with giving money, now you're giving weapons. So that's fine.

If you let your own citizens (some of whom are veterans) go to Ukraine to enlist, that's their own business. Ukraine can accept or deny them, but there's no ability for the home country to prevent them from joining.

But if the country sends active troops to Ukraine, does that count as an implicit declaration of war against Russia?

Not that France is at any risk. Russia would be unlikely to strike within France, and if they did, France would go to full war with Russia, and Russia would lose.