Yvert et Tellier is a postage stamp dealer and a philatelic publishing company founded in 1895 in the northern French city of Amiens, where the head office is still located.
It is a pun on the name of the company: hiver, été liés ("winter, summer together") sounds a lot like the French pronunciation of Yvert et Tellier.
He discovered stamp collecting thanks to Tellier, a philatelist, who had already added a small philatelic newspaper, L'Écho de la timbrologie, to the papers printed by the company.
Henri ran the printing works, his brother Pierre directed L'Écho de la timbrologie, and Jean Gervais took care of the publishing.
Yvert has been fighting on two fronts: it has successfully defended the rights to its numbering system, and it distributes a free CD-ROM with its French stamp catalog.
Eugène Yvert (circa 1794-1878), journalist, and founder of the printer company in Amiens where he moved to create a legimist paper.