When I was last there in 2012 I was followed - not just around a neighbourhood, but onto the Metro and to a restaurant where I met my friend, by a guy wearing traditional Arab/Muslim looking garb. I can't say for sure that he was either, but based on skin tone and clothes.
The look he gave me when I looked over and saw him (because I hadn't noticed him follow me once I left the neighbourhood I was in, and relaxed thinking it was all just a weird coincidence) was enough for me to insist my best friend pack her stuff - we got on the Eurostar back to London that night, at a fantastic cost of last minute tickets.
Honestly I don't ever want to set foot back in Paris between that incident and hearing the stories coming out of there. I know that there must be a LOT of media scaremongering, but the stories I see in the news and things I hear from European friends makes me question the safety of going to Western Europe as a single woman.