Bouygues Telecom plans to announce hundreds of job cuts later Tuesday to combat a mobile phone price war in France, Les Echos reported citing unidentified sources.

France's third-largest mobile phone company, a unit of industrial conglomerate Bouygues SA (EN.FR), will announce the cuts at a meeting Tuesday afternoon, as part of a voluntary departure plan, the newspaper added.

A spokeswoman for Bougues declined to comment.

The French telecommunications sector has been locked in a brutal price war since January, when Iliad SA launched a cut-price mobile phone operator Free Mobile. The new operator attracted 2.6 million subscribers in the first three months of the year, forcing France Telecom SA (FTE.FR), Vivendi SA's (VIV.FR) SFR and Bouygues to cut prices to compete.

SFR also plans to announce a strategic plan to its unions Tuesday. Unions have said the company will likely seek cost cuts, and has already outlined cuts of 450 million euros ($567.7 million) for 2012. Among targets for cost cuts are call centers, the union officials added.

SFR's new chief executive, Stephane Roussel, who took over last week, declined Monday to specify what the strategic plan would entail, saying only that it is "ambitious."

Newspaper Web site: http://www.lesechos.fr

-Write to Sam Schechner at sam.schechner@wsj.com