The question remains as to how to deal with this problem without becoming like a certain nation that flushed its freedoms down the toilet.
Bin Laden types are hard to track, that requires serious intelligence work. But for those who blow up themselves and kill people like these two did two days ago, it is rather easy and regular police can do it. Just monitor those miserable types among muslim population, 15-40 years old, without children and any reasonable future. There are a lot of them but it is better to put extra funds to make sure this doesn't happen again than to let people die because you can't budget the operation.
Muslims are making this harder than it should be, even though they deny it. They stick together, like a clan in cRPG when a bad seed member is acting like a douche and everybody is standing by his side. If they openly denounced those potential terrorist who are already involved in criminal activity on Parisian streets it would be easier for the police and no one would brand it as anti-mulim or anti-muslim actions but action against dysfunctional members of society which it essentially is.
Condemning crimes is not enough. Muslims in Europe should openly stand against violence and condemn those among them who are sociopaths. Only that way they will not be branded as religion of hatred and wrong values.