* Would value SFR at around 15 bln euros - source
* Vivendi would keep 30 pct of merged company - source (Recasts with confirmation of talks, context, shares)
By Leila Abboud and Gwénaëlle Barzic
PARIS, Feb 24 (Reuters) - French media group Vivendi confirmed on Monday it had been approached by cablegroup Altice over a tie-up between mobile operator SFRand cable firm Numericable, but said it had not yetreceived any formal offer.
The proposal being discussed would value Vivendi unit SFR ataround 15 billion euros ($20.6 billion) and would see Vivendikeep a stake of roughly 30 percent in the new company, a sourceclose to SFR told Reuters earlier. A second source cautionedthat it remained to be negotiated what proportion of the newcompany the two sides would own.
A deal would accelerate Vivendi's exit fromcapital-intensive telecoms as it tries to focus on pay-TV andmusic, and would enable SFR to spend less on rolling outhigh-speed fibre broadband in France by relying on Numericable'snetwork.
Les Echos newspaper first reported on the talks on Sunday,saying the parties aimed to reach a firm deal in a few weeks. Itwould involve an issue of about 8 billion euros of debt, thepaper added.
Analysts have estimated the potential financial benefits ofthe pairing could be worth as much as 6 billion euros.
A Vivendi spokesman declined to comment beyond saying thatno memorandum of understanding had been signed for now. Both SFRand Altice, the holding company of founder Patrick Drahi,Numericable's largest shareholder, declined to comment.
A partial exit from SFR would cap a tumultuous period atVivendi, once Europe's biggest media and telecom conglomeratebuilt during an acquisition spree in the late 1990s.
The past two years have been a period of soul-searching forthe company after it came to realise its various businesses didnot make much sense together and Chairman Jean-Rene Fourtou lostenthusiasm for the telecoms business.
With the arrival in late 2012 of Vincent Bollore onVivendi's board as the group's largest shareholder, thestrategic review has gathered pace. It agreed to sell itssecond-biggest unit, Maroc Telecom, to Gulf operatorEtisalat last year. The divestment is expected to close soon.
Drahi, Numericable's largest shareholder, has made no secretof his interest in a tie-up with SFR. The two sides heldunsuccessful discussions in late 2012 but Vivendi wasunconvinced by Drahi's proposal and price.
Since then, Drahi carried out initial public offerings ofboth Numericable and Altice to bolster his financial firepowerand borrowing ability and to take another run at buying SFR.
SFR HIT BY PRICE WAR
Shares in Numericable were 4.3 percent higher at 30.74 eurosat 1225 GMT. Vivendi shares were up 1.3 percent.
"There should be significant synergies from such anoperation, namely with the migration of SFR fixed broadbandcustomers to Numericable's cable network," Espirito Santoanalysts wrote in a note.
A deal would allow SFR to use Numericable's lines into homesrather than renting those of its rival Orange. Thetie-up would also lower the cost of rolling out high-speedbroadband fibre, something Numericable has already heavilyinvested in.
Vivendi's former cash generating machine, SFR has beenhammered by a price war started when rival Iliad undercut it with its low-cost "Free Mobile" offer, forcing it tospend money to try to keep clients.
Numericable, which listed on the stock market in November inFrance's biggest initial public offering since 2009, hadpreviously been seen as a potential takeover target for SFR andrival Bouygues Telecom.
Altice, which also owns French and Belgian cable companiesand mobile operations in Israel, listed on the stock exchange atthe end of January.
Built via a decade of acquisitions, Altice is surfing a waveof investor interest in the European cable sector as a growingnumber of consumers turn to those companies for television andbroadband at faster speeds and lower prices than from telecomsrivals. ($1 = 0.7275 euros) (Writing by James Regan and Natalie Huet; editing by Eric Walshand Tom Pfeiffer)
Vodafone (VOD)