Letter Post

[copey]

Could you please let me know how I should address an envelope to a French household (Mr and Mrs ?......)

[incitatus]

The simplest would probably be: M. et Mme X

[vittoria]

You can address it as Famille Xyz.

[artisan]

If it's the family Cherauc say, couldn't you say 'Mesdames Cherauc' ?

[allen ives]

http://world.altavista.com/ might be useful in future. It's supposedly a Babelfish translating engine, good enough for Mr and Mrs, but watch it for more complicated thoughts.