Cell towers in Cergy (Val-d'Oise)

Masts stand at Les Maheux, Rue la Croix Saint-Sylvere, 23 Boulevard du Port, Parc St Christophe, Passage des Espaliers and Rue de la Croix des Maheux.

Systems from 1998 are still on the register. Local 5G started with Bouygues Telecom in November 2020; Free Mobile followed in December 2020, SFR followed in April 2021. 2013 was the busiest year, with 57 new systems, most of them 4G.

Over the past 12 months ANFR recorded 48 new systems here. Approved additions not yet in service are pending on 11 existing masts, for example Bouygues Telecom (4G and 5G, including 5G at 3.5 GHz) at Les Linandes, Free Mobile (4G and 5G, including 5G at 3.5 GHz) at 1 Impasse des Rougettes and Free Mobile (5G 700 MHz) at 8 Rue du Ponceau. 19 Bouygues Telecom 5G transmitters are listed as technically operational — installed, but not yet declared commercially in service.

Most antennas sit on rooftops (38 of 44), so heights stay modest; the tallest support is 49 m at Les Maheux.

Only one mast carries all four networks; 14 supports carry only Free Mobile.

Among the 43 Val-d'Oise towns with at least five masts, Cergy ranks 2nd by mast count.

On 3.5 GHz, the fastest 5G band: Free Mobile on 17 of its 19 masts, Orange on all 13 masts, SFR on 10 of its 12 masts and Bouygues Telecom on 9 of its 12 masts.

Nearby, Eragny (2.8 km to the south-east) has only 9 masts.

At 15 km² with 70,906 residents, the commune is dense enough that most antennas sit on rooftops rather than pylons. It is part of the CA de Cergy-Pontoise intercommunal grouping.

Most of the town's 44 masts are buildings (38).

Figures above cover installations declared to ANFR as in service or technically operational, as of October 2026; approved projects are not counted.