Criteo, which sells personalized display ad management services, has bought Tedemis, another France-based firm that offers targeting services for online marketers but which focuses on e-mail. Criteo says it will pay up to 21 million euros (US$28.8 million) for Tedemis.

Criteo launched in 2005, while Tedemis debuted in 2006. Tedemis serves more than 200 clients, most of them located in France, Criteo says. Criteo says it serves more than 5,000 companies, operates 16 offices around the world and employs 800.

“The increased consumption of e-mail via mobile presents an exciting opportunity for advertisers,” says Eric Eichmann, Criteo’s chief operating officer. “We will be deploying Tedemis’ solution starting with our key markets as part of Criteo’s expanded product portfolio.”

Consumers increasingly read e-mails on their mobile devices rather than on desktop PCs, according to a January report from e-mail marketing technology provider Movable Ink. In the fourth quarter of 2013, 64.75% of e-mails in the U.S. were opened on smartphones or tablets versus 35.25% on desktop computers. Those rates show a shift toward more mobile e-mail opens from the quarter prior, in which consumers opened 60.81% of e-mails on a smartphone or tablet versus 39.19% on a desktop.

A recent study from Experian Marketing Services pointed out the power of personalized e-mails: When retail chains sent out e-mails with personalized subject lines, the open rates  for those messages were 37% higher than messages without personalized subject lines, according to the report entitled “2013 Email Market Study.”