We have booked a return ticket from Vienna to Delhi. The entry ticket is from Jet Airlines from Delhi to Paris.

Would it be problematic if:
We go by Jet Airlines from Delhi to nice, or Paris 
And return from Vienna to Delhi by Air India
The PNR is different in this case. 
The ticket will not be on one page.
We applied for a schengen visa from France, will it be mandatory to spend max time of stay in France