It is a general-interest, news, talk and music station, broadcasting nationally ("category E" as classified by the CSA) in France, Francophone Belgium, and Luxembourg.

Until 2022, RTL was also broadcast on long wave frequency 234 kHz from Beidweiler which could be picked up in large parts of the continent.

The Société Luxembourgeoise d'Études Radiophoniques (SLER) was founded on 11 May 1929 with the aim of obtaining an eventual broadcasting contract from the Luxembourg government.

This company was run by Luxembourger François Anen, French publisher Henry Etienne, and French engineer Jean le Duc representing the Compagnie des Compteurs de Montrouge, which possessed 84% of the project's capital and had signed a secret agreement to work with the group CSF, the main stockholder in Radio Paris.

On 14 January 1933, experimental broadcasts by Radio Luxembourg began at 1191 metres (200 kW), an unauthorized wavelength, from the longwave transmitter at Junglinster.

In the 1960s, it was faced with the success of another peripheral network from Germany, Europe 1, which adopted a modern tone and attracted a young audience.

During the May 1968 civil unrest and protests by workers and students, the French public radio networks were on strike and TV was not independent from the government.

Whereas Luxembourg's English service was always centred on light entertainment and popular music, RTL France is a mixed station.

Radio Luxembourg's two main national competitors are Europe 1 (another out-of-country commercial station, broadcasting from Saarland, again with Paris studios) and the state-owned France Inter.