Intelligence sharing is a good idea, but the Nice attacker appears to have been an individual with mental health issues and no known fundamentalist tendencies.

Intelligence sharing is a good idea, but the Nice attacker appears to have been an individual with mental health issues and no known fundamentalist tendencies. His family and associates probably knew something was wrong with him; he threatened his ex and was violence prone at times. Unfortunately, there's not a lot you can do, especially in a free society, unless the person runs afoul of the law. If they stay out of trouble, they can plan horrific attacks at a time of their choosing. The only thing I can think of is to have more available mental health services including residential treatment facilities, and make it easier for concerned families to get someone the help he needs before a tragedy occurs. Probably in an immigrant community, there's the shame factor to deal with as well; so discretion and confidentiality would be highly important. Beyond that, France and other countries taking in large numbers of immigrants and asylum seekers from troubled regions need to obviously limit the numbers and scrutinize each applicant more carefully. Easier said than done, but they have to try.