Seine River cruises:
Introduction
Bateaux-Mouches
Bateaux Parisiens
Vedettes de Paris
Vedettes du Pont-Neuf
Batobus ('hop on, hop off' boat)

St-Martin Canal and Marne River cruises:
Canauxrama
Paris Canal

Other tour-boat operators in Paris:
More boat cruises

Related article:
Dinner Cruises on the Seine