To check your connection possibilities we recommend to use service of Skyscanner. For instance one-way tickets between London Luton and Paris (CDG) are available for Ł38 with EasyJet. Promotional offer is valid for flights in travel period between September 2014 and February 2015.
Booking samples
Paris - Mumbai - London for Ł261 (€326)
Paris - Mumbai and New Delhi - London for Ł269
Paris - Mumbai and Chennai - London for Ł270
Paris - Mumbai and Kochi - London for Ł284
EN - Frankfurt - Mumbai - London for Ł302 (€378)
DE - Frankfurt - Mumbai - London for €392
Travel date samples (based on routing Paris - Mumbai - London)
9. - 24.9.
30.9. - 15.10.
8. - 23.10.
10. - 26.11.
25.11. - 7.12.
20.1. - 7.2.
9.2. - 28.2.
Alternative - If you are planning to visit India within next main tourist season 2014/2015 you may also consider roundtrip flights from many European countries with various airlines as listed in our article. Please refer to this link if you are interested in this deal, the cheapest return flights to Mumbai are currently available for €368.
Booking sample of cheap open-jaw flights to India with Gulf Air for Ł261 here. In this case you would be departing from Paris to Mumbai on 21st of January and returning from India back to London for 7th of February 2015.