The disagreement concerns the Sanofi chairman Jean-Francois Dehecq who backs a transformational deal with Bristol, and the chief executive Gerard Le Fur who believes it is important to focus on Sanofi's internal research and development program.
The Times did not cite its sources, but claimed there was a significant difference between the men's tactics.
Sanofi has denied there is any rift in the company and also declined to comment on whether a Sanofi-Aventis, Bristol merger would go ahead. It was reported last month that Sanofi cut short talks about a possible merger because of concerns surrounding legal costs related to the drug Plavix, which the two companies collaborate on. The companies are currently involved in a legal dispute relating to the Plavix patent.
The Times said that the merger talks may resume if the chairman's views are adopted and the Plavix litigation is settled. The acquisition would create one of the largest pharmaceutical groups in the world.