French mobile operator SFR and two key unions on Thursday announced they have reached a deal to shed a third of the company's staff through a voluntary departures plan.

The decision to cut 5,000 jobs came two years after SFR was bought for more than 17 billion euros ($19 billion) by Altice, a holding company owned by French-Israeli businessman Patrick Drahi.

An agreement on no forced job cuts included in SFR's purchase expires in July 2017, and Drahi said in June the company is "over-staffed".

France's second-largest mobile operator currently employs more than 14,000 people. 

The backing of the unions, Unsa and CFDT, is enough to ensure the draft deal proposed after a meeting with Labour Minister Myriam El Khomri on Tuesday goes through.

With unemployment hovering just under record highs and elections approaching next year, the French government is keen to limit mass layoffs.

The CGT, a more hardline union, has announced it does not support the deal.

Les Echos reported the restructuring will cost some 600 to 800 million euros ($670 to $890 million) over two years, but will bring savings of some 400 million euros a year.

In an email to all SFR employees, CEO Michel Paulin said a deal with the unions had been reached.

Unsa confirmed it had backed the deal. CFDT said in a statement it had also signed a deal. 

CFDT's Isabelle Lejeune-To told AFP it "seems absurd to us to shed a third of the company staff," but added the union was working to get the best deal for members.