By Ruth Bender 

PARIS--Cable tycoon Patrick Drahi Saturday trumped rival Bouygues SA in the battle for SFR as Vivendi SA's board voted in favor of selling its phone unit to Altice SA, ending a month-long feisty bidding war between two very keen suitors.

Vivendi said its board unanimously voted for a bid from Altice that includes 13.5 billion euros ($18.5 billion) in cash when the deal closes, plus a potential further payout of EUR750 million. Vivendi would also hold a 20% stake in a new group formed by merging Altice's French cable operator Numericable Group SA with SFR, with the option to exit the stake at a later stage.

The board's decision comes after an intense bidding war, which culminated Friday, when Bouygues submitted a final sweetened offer ahead of the crucial board meeting that stretched from Friday into Saturday.

Vivendi has sought to shed its telecoms assets for the past two years in a bid to refashion itself as a media and content business. The group initially planned a spinoff of the unit--which accounts for close to half of its sales--but then attracted bids from Bouygues on top of Mr. Drahi, who has chased SFR for several years.

Vivendi three weeks ago entered into exclusive talks with Altice but Bouygues since came back with new offers in a bid to squeeze out Altice.

Vivendi said it has "attentively" examined all offers, including those from Bouygues, but decided that Altice's proposal offers the best potential to create value for shareholders, employees and clients.

The proposed deal to merge Altice's Numericable with SFR is still subject to the approval from relevant antitrust bodies and consultation with employee representatives.

Write to Ruth Bender at Ruth.Bender@wsj.com

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