Cell towers in Conflans-Sainte-Honorine

Declared supports include 1 camouflaged "tree" pylon, with buildings making up most of the remainder.

Antennas are listed at rue des Ambassadeurs, 1 Rue de Stalingrad, La Justice, 17 rue de la Résidence des Clos, La Croix Rouge and Station Bp les Hautes Coutures Rn184.

Over the past 12 months ANFR recorded 33 new systems here. ANFR has approved 2 new sites that are not live yet, plus additions on 6 existing masts. New: Bouygues Telecom (4G and 5G) at 126 avenue Marechal Foch and SFR (4G and 5G, including 5G at 3.5 GHz) at 24 Boulevard du Général de Gaulle. 20 Bouygues Telecom 5G transmitters are listed as technically operational — installed, but not yet declared commercially in service.

Systems from 1995 are still on the register. Bouygues Telecom opened 5G here in November 2020; Free Mobile followed in December 2020, SFR followed in December 2020. 2021 was the busiest year, with 36 new systems, most of them 5G.

Most antennas sit on rooftops (15 of 23), so heights stay modest; the tallest support is 34 m at La Justice.

On 3.5 GHz, the fastest 5G band: Bouygues Telecom on 9 of its 11 masts, Free Mobile on 9 of its 10 masts, Orange on all 5 masts and SFR on 3 of its 5 masts.

Nearby, Eragny (1.7 km to the north) has only 9 masts.

Only one mast carries all four networks; 6 supports carry only Bouygues Telecom.

Among the 62 Yvelines towns with at least five masts, Conflans-Sainte-Honorine ranks 8th by mast count. With 23 masts for 36,958 residents, or 6 per 10,000, it has fewer masts per inhabitant than the median for those towns (7).

At 10 km² with 36,958 residents, the commune is dense enough that most antennas sit on rooftops rather than pylons. It is part of the CU Grand Paris Seine et Oise intercommunal grouping.

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