Though some US legislators expressed concerns about Google’s growing power in online advertising, one big ad firm welcomed Yahoo’s search ad agreement with Google.

In the US, Microsoft and Congressman Joe Barton (R-TX) publicly fretted about the increasing control Google possesses over contextual search advertising. High-ranking Microsoft executive Kevin Johnson complained in France about Google taking over 90 percent of the search ad market.

Another Continental concern expressed no concern about Yahoo turning to Google to possibly deliver $800 million in ad revenue in the first year of their partnership. The Guardian cited Maurice Levy, head of Publicis Group, who expressed a positive view of the deal between the former search ad rivals.

Speaking in Cannes as Johnson did, Levy put forth the idea that Google and Yahoo could share search data and come up with better ad campaign targeting for their clients. Publicis is a partner with Google on ad technology.

With Barton in the House and Herb Kohl (D-WI) in the Senate asking questions about antitrust and privacy concerns, the idea of Google and Yahoo mixing and matching user data to their heart’s content may pull sharper focus onto a deal the two companies believe has no reason to fall under regulatory scrutiny.