We would have to be brain dead to rule out the real possibility of that. IMO, baring *clear cut* evidence that it was not Muslims, I would make my bets that it was.
Muslims are running amok in Paris, basically attacking churches (and non Muslims). We don't even have an accurate count of how churches and how much damage they are causing.
In the absence of concrete evidence that it was an accident, it is only logical and prudent to consider them the primary suspects.
Given the spate of church desecrations apparently happening in France, and that is a week before Easter I agree that until I hear otherwise, I give credence to muslim involvement.