Where can a buy Luxemburg Champagne in the United States or Canada?
The brand is am looking for is "Bernard Massart", but any other
Luxemburg Champagne would suffice. I need between 3 and 12 bottles.

Unfortunately, your search for Luxemburg Champagne will remain
unscuccessful because such a thing as "Luxemburg Champagne" does not
exist. Only sparkling wines from an exactly defined region of France
(the Champagne) may be called Champagne. This is even protected by
European laws. All other sparkling wines are just that - sparkling
wines (which does, of course, not say anything about their qualities).

Scriptor

"Luxembourg makes a lot of wine for a little country: some 17 million
cases a year. The Luxembourgers drink most of what they make, then
share what?s left with their neighbors, the Belgians and the Germans,
with just an errant bottle or two finding their way into France.

'We have a market for all we can make,' said Frank Linster, sales
manager of Les Domaines de Vinsmoselle, a big cooperative. 'It really
wouldn?t pay us to go after major markets like the United States' "

http://info.detnews.com/wine/winenews/details.cfm?id=381

The Bernard-Massard website lists these sparkling wines:

http://www.bernard-massard.lu/en/cave/cremants_vins_effervescents/liste_produits.php?rubrique=19&categorie=26