I don´t think that any of the 4 mobile phone companies offer 4G/LTE service for prepaid customers; something you should ask about.

The low cost option might be Lycamobile which uses the Bouygues network. Their SIMs are available at tabacs and magazine stores such as Relay. European mobile phone operators use 900/2100MHz for 3G transmissions so check that your phone can receive 2100MHz (any quad band phone will have 900).

The #1 problem with reception is improperly configured APNs. They´re easy to set up and are provider specific. A quick search can tell you the correct settings and how to change them if needed.