Seems more likely to me that Ukrainian forces are just seeking any way they can to hurt Russian forces. If Russian mercenaries are making money that funds the invasion of Ukraine and making allies for the Russian government by fighting in Africa and the Middle East, it makes sense for Ukraine to attempt to counter that where they can. It's also pretty reasonable for Azawad fighters to see Ukraine as an ally given that they're fighting a Russian-backed government employing Russian mercenaries.
We know that for a while now. Not sure what stupid shit you're insinuating in your second paragraph there but of course Ukraine is going to disrupt Russian operations everywhere they can now.
Uhm.. why would you think that France will not do these things. Russia is actively sawing at the legs of France's empire in Africa. Via Wagner Russia is already in open hostilities with France. A lot of people are just not paying attention to that. I can't imagine troops deployed in country where they can get caught easily, but programming scalp missiles, direct liaison to NATO, advisory roles, hell even manning artillery or AA weapons behind the lines. much is possible.
This means nothing actually. Wagner showed itself operating in Africa as there were Russian flags in all countries where a revolution happened recently. In return I imagine those countries are helping Russia.
In this context, showing a Ukrainian flag is a fuck you to russia as much as it could be something more important. It's hard to tell from only a picture.