Buying back L'Oreal's 9% stake in Sanofi could be "very accretive" for the French drugmaker, although the idea remains speculative, Sanofi's CEO Chris Viehbacher told the news agency Reuters on Friday on the sidelines of the World Economic Forum in Davos, Switzerland.

Investor attention has focused increasingly on a potential realignment of shareholdings that may see Sanofi making a debt-funded repurchase of L'Oreal's stake in a move analysts believe should boost the pharmaceutical group's earnings.

Although the €9 billion holding has yet to be put up for sale, such a deal could provide Sanofi with a useful lift as it seeks to return to growth after a difficult 2013 that featured problems in Brazil and several product setbacks.

"If you get the chance you are certainly going to look seriously at it, but it is an 'if, if, if' situation," Viehbacher said. "It could very well be, when you get there, that it could be a very accretive thing to do," he added.

L'Oreal's CEO Jean-Paul Agon said last year the cosmetics company could buy back the 29.5% stake Swiss food group Nestle holds in it, if L'Oreal in turn sells the stake it owns in Sanofi. Agon reaffirmed last week that his group had the firepower to buy Nestle's stake. Restrictions on Nestle selling its L'Oreal holding end in April.