Was the idea to kill them off in Ukraine to begin with?
In normal French activities, France has been arresting and prosecuting Nazis since WWII.
The French consider them Far Right as opposed to Communists who are Far Left.
However the Foreign Legion has had regular association with Far Right members and many French Mercenaries are considered Far Right and are accepted.
It seems Far Right Frenchmen are not denigrated when they act to protect French Women and Children, but action is taken if they ire Leftist Socialist Government insiders, the same sort of treatment as of ordinary citizens and Yellow Vests.
France may have developed a Good Nazis and Bad Nazis differentiation based on current events.