The Wall Street Journal reported today that Publicis, a French advertising company, is at the top of the list of potential buyers for Redmond, WA-based Microsoft’s digital advertising group Razorfish in Seattle. According to the Journal’s sources, Publicis has bid between $500 million and $600 million for Razorfish, which Microsoft acquired in 2007 as part of a $6 billion deal for aQuantive. Other bidders for Razorfish include Dentsu, the largest advertising firm in Japan.