While in a perfect world French Jews and religions/ethnicities of all types would be able to be open about their identities, our world has become a violent place. For the moment it is only smart that they keep their identities hidden and therefore stay safe, at least until things clear up a bit.
No, I do not believe that French Jews should follow the request of the head of Marseille's Israelite Consistory and hide their identity. Forcing the Jews to hide their identity is a form of suppression. Societies around the world have become accepting of various cultures, groups, and religions. Forcing the French Jews to hide their cultural and religious identity suppresses their civil rights and liberties. Instead of requesting them to hide their identity, they should receive more protection.
In today's world, everyone should be able to practice their religion in public, as long as it doesn't interfere with others. People should be proud of their heritage, no matter who they are or where they're from. I think it would show strength and solidarity for Jews to openly show themselves. It would make a statement, and bring people together. Change can only be made by the people, and hiding people cannot change things.
If French Jews follow their Israelite Consistory and hide their identity, this easily can be compared to having to hide their identity from the Nazis and Hitler in World War II. These innocent people should express themselves and their religion (peacefully) as they always have done. However, if they do not feel safe, then it would be smart to do anything in their power in order to feel safe, but they should not have to follow a request to "hide their identity".