PARIS, March 27 (Reuters) - French drugmaker Sanofi plans to launch its new Toujeo insulin for diabetics in the United States on Monday, according to a source familiar with the matter.

Toujeo was approved for use in the United States on Feb. 25 and was recommended for approval by European regulators two days later. Sanofi has previously said it planned the launch for the beginning of the second quarter.

Toujeo is expected to face fierce competition from early 2016 from Tresiba, an rival ultra-long-acting insulin developed by Denmark's Novo Nordisk.

Novo Nordisk on Thursday said it would resubmit Tresiba to U.S. regulators based on interim analysis data from a clinical trial, bringing its biggest new drug hope closer to the world's top market.

Tresiba was rebuffed by U.S. regulators two years ago. Eli Lilly is the other main U.S. insulin market player.

(Reporting by Andrew Callus; Editing by Ben Hirschler)