Well, we can all read the tweet, and there was no threat or encouraging violence there.
Actually, I do read incitement into it. Maybe my imagination but that’s the way I see it.
Reminds me of a friend of mine who lives in Paris and said: you love the French until you find out what they’re saying.
The violence is implied by Dieudonne, well known for his popularizing the quenelle gesture, a covert Nazi salute mocking those in authority.
More here: It's known as "La quenelle." It's a modified Nazi salute for Muslim solidarity against the Jews. It's also used by neo-Nazi skinhead groups and members of the rap/hip hop community in France as an expression of extreme disdain for Jews in Europe and Israel.