Looks like a desperate attempt by protest groups to try and damage the French national front on the run up to elections. I doubt giving Marine Le Pen more media attention so she can play the victim and portray this as a free speech issue will damage their electoral chances.
She's got no chance in the election.
The article you linked to refers to upcoming local elections and links to polling suggesting NF gains.
The next electoral test is in December http://www.politico.eu/article/poll...-for-victory-france-national-front-elections/
I doubt their momentum will lead to a National election victory but they do seem to have increasing popularity. Any more Islamic terrorist/extremist atrocities on French streets could make it a close run thing.