According to a Havas insider, Mr. Farella's exit followed philosophical disagreements with a new management team within the media holding company, Media Planning Group, which is led by CEO Tony Rusich.
Mr. Farella declined to comment. Mr. Rusich could not be reached at press time.
Havas recently lost out on a bid to acquire Tempus Group and its media shop CIA, which would have been merged with Media Planning. Also, Media Planning Group is attempting to fold sibling Arnold Worldwides's media unit into the unbundled shop.
It has already begun the process of merging the media departments from two other sibling shops, Jordan McGrath Case & Partners and Messner Vetere Berger McNamee Schmetterer Euro/RSCG.
Executives familiar with this process have said these mergers have not proceeded smoothly.
The agency also is in the middle of a intensive search to fill the high-profile position of chief broadcast buyer. The job remains unfilled.