Cell towers in Chilly-Mazarin (Essonne)

Declared supports include 1 water tower and 1 bridge or viaduct, with pylons making up most of the remainder.

Declared locations include La Fontaine Augere, La Sabloniere, 31 Avenue Pierre Brossolette, 28 Rue du Pont des Maures, 28 RTE de Longjumeau and 7 Avenue Arago.

8 systems were switched on in the past 12 months. ANFR has approved 2 new sites that are not live yet, plus additions on 3 existing masts. New: Bouygues Telecom (4G and 5G) at 29 rue Pasteur and Free Mobile (3G, 4G and 5G, including 5G at 3.5 GHz) at 115 Route de Massy. 4 Bouygues Telecom 5G transmitters are listed as technically operational — installed, but not yet declared commercially in service.

2015 was the busiest year, with 12 new systems, most of them 3G. Free Mobile opened 5G here in December 2020; SFR followed in March 2021, Bouygues Telecom followed in July 2021. The oldest transmitter still listed here goes back to 1998.

ANFR lists a 49 m water tower at La Sabloniere as the tallest structure. The median height of measured supports is 25 m.

Of the 9 masts in the commune, SFR is the only carrier on 3 masts.

3.5 GHz 5G is declared by Orange on all 3 masts, Bouygues Telecom on 2 of its 3 masts, Free Mobile on 2 of its 4 masts and SFR on 2 of its 3 masts.

Nearby, Morangis (2.1 km to the south-east) has a higher 5G share (100%).

By mast count, Chilly-Mazarin is 38th of the 60 Essonne towns that have five or more. With 9 masts for 20,443 residents, or 4 per 10,000, it has fewer masts per inhabitant than the median for those towns (7).

Source: operator declarations to ANFR, as of October 2026. Projects that are only approved are left out of the totals.