Practically all the major Champagne labels offer tours; the Office de Tourisme (beside the cathedral, at 2 Rue Guil?­laume de Machault) is the best source of information on hours and prices.
Just about all of the champagne makers offer tours. 
mnli hypothesis: Just about all of the champagne makers offer tours.  premise: Practically all the major Champagne labels offer tours; the Office de Tourisme (beside the cathedral, at 2 Rue Guil?­laume de Machault) is the best source of information on hours and prices.