Changing assurers for Decennale

Quick question. Is it correct that a professional assurance, cannot be cancelled in less than the contracted time, ie, 2 months and that Loi Chatel cannot be applied?

I would have been quite happy to stay with my existing assurers until I got the renewal notice which, this year has gone up by 400 Euros. Obviously by this time it is too late to cancel. I should have done what the French apparently do and get quotes in earlier but it came as a shock, especially as I do wonder about the value of these policies. They dont seem to benefit client or entreprise.