Sanofi recently approached lenders such as Citigroup Inc and Bank of America Corp about funding a higher bid, the report said. Sanofi has said it already has financing from J.P. Morgan Chase & Co, BNP Paribas SA and Societe Generale SA.
Sanofi has asked Genzyme to quote a price that would be high enough to spur the biotech company to start talks, but the biotech company has refused to name a pricetag, the report said.
The French drugmaker wants to reach a friendly agreement but has not ruled out a hostile offer made directly to Genzyme shareholders, sources previously told Reuters.
Last month, Genzyme rejected Sanofi's $69 per share offer as dramatically undervaluing the U.S. company and not a bid that justified entering merger talks.
Sources previously told Reuters that Genzyme sought an offer of at least $75 per share before Sanofi could review its books, while some investors want up to $80 a share in a deal.
Genzyme shares on Friday closed at $71.60 on Nasdaq.
Sanofi wants to buy Genzyme, a leading maker of drugs for rare diseases, to fuel growth as some of its key treatments lose patent protection.
Sanofi and Genzyme could not immediately be reached for comment.