Three French telecoms giants said on Saturday they had signed a deal to buy rival SFR after months of negotiations over a takeover of the ailing firm.

The companies – Bouygues Telecom, Orange and Free owner Iliad – said SFR parent Altice had accepted their offer of 20.35 billion euros for the struggling mobile operator.

The deal could reshape the French telecoms landscape by reducing the number of main operators from four to three.

It is "one of the largest industrial transactions in the telecommunications sector in Europe," the companies said in a joint statement.

The deal includes a potential bonus of up to 650 million euros on closing the sale, and a promise to SFR employees not to cut any jobs until 2029.