"Pro russian far left" is the rhetoric used by the Macron government, the parties of this union have consistently condemned the Russian invasion, the program they revealed mentions :

Defend Ukraine and peace on the European continent to thwart Vladimir Putin’s war of aggression, and for him to answer for his crimes before international justice: to defend unwaveringly the sovereignty and freedom of the Ukrainian people as well as the integrity of its borders, by delivering necessary weapons, cancelling its foreign debt, seizing the assets of the oligarchs who contribute to the Russian war effort within the framework permitted by international law, sending peacekeepers to secure nuclear power plants, in an international context of tensions and war on the European continent and working towards the return of peace

Far left in France has a specific definition that seems to be blatantly disregarded by french politicians : those who want to take power via a revolution are far left, this union is playing the game of gaining power through the popular vote