Court Sejours Circulation

I have been given a Schengen Visa from the French Consulate in Dubai. It is a type C visa valid for 2 years, with 90 day stay allowed. Non Professional and also is written 'Court Sejour Circulation'.
I need to understand what does this mean exactly, is it allowing me 90 days in total over a 2 year period, or does it mean I can stay 90 days every six month period if necessary. Please help.

During the validity of your visa (2 years), you can stay a maximum of 90 days every 6 months in the Schengen space.