Swagatam Bro

     No you dont need visa while travelling through paris and Bahrain.

If you have long transit in Bahrain i.e more than 12 hours in Bahrain ( most people will have that), then when you land on the Bahrain Airport you should get a boarding pass to kathmandu and over there tell them that you have more than 12 hours of transit and you need a hotel to stay. Then they will book a hotel for you free. Then yo have to have that slip and go to imigration in the gate. Then they will give you visa for one day over there.

You dont have to worry over here about visa.

Enjoy your flight on Gulf air. Do not put any electronic in the luggage, if you do so you will never receive your luggage. Be prepared to receive your luggage a day after you land on Kathmandu.

Have a safe trip.