Sanofi declined to comment on Thursday on media reports that a lawsuit filed in the United States by a former employee alleges that the French drugmaker paid $34 million in kickbacks for doctors, pharmacies and hospitals to order its diabetes treatments.

CNBC said that a suit filed in Newark, New Jersey, targeted several Sanofi executives including former chief executive Chris Viehbacher, who was sacked following a board dispute on Oct. 29 after six years at the helm.

The CNBC report said Diane Ponte, 53, claims she reviewed contracts that were intended to fund kickbacks.

Ponte was fired in September, after allegedly suffering retaliation for bringing the scheme to light, CNBC said.

A Sanofi spokesman said in an e-mail on Thursday that the company doesn't comment on litigation. Viehbacher could not immediately be reached for comment.

The company said last month its diabetes business, which includes Lantus, the world's most prescribed insulin and the firm's top-selling drug, is set to post little or no growth through 2018.