Far-left militants are suspected of being behind Quentin Deranque's death and the party of Jean-Luc Mélenchon is being widely condemned.

Quentin Deranque, 23, was beaten to death by far-left activists in France's Lyon last week.

Several suspects had been flagged as national security threats due to their ties with the antifascist group Jeune Garde. Two of them worked for MP Raphaël Arnault, the founder of…