RTL9 is a French-language Luxembourgish television channel shown in Luxembourg, France, Monaco, Africa and the French-speaking regions of Switzerland.

On 20 May 1953, the administrative council of la CLR authorised their president, Robert Tabouis, to sign a contract with the Luxembourg government to run a television channel.

On 23 January 1955, the date of her 59th birthday, the Grand Duchess Charlotte I launched Télé-Luxembourg with her husband, Prince Félix, marking the official birth of television in Luxembourg.

The channel, which was then broadcasting for thirty hours per week, eventually was becoming noticed by the viewing public, and became a part of the audiovisual landscape.

It was marked out by its sense of levity (gameshows, soaps, and nightly films) and fun (strong presence of French presenters such as Pierre Bellemare and Georges de Caunes and announcers such as Anna-Vera).

The popular success was so high that their efforts were recognised by hosting the 7th Eurovision Song Contest in 1962 shown across Europe from the Villa Louvigny.

Coditel installed a reception station in the Ardennes at Saint Hubert and broadcast a signal from Télé-Luxembourg via cable from Namur, Brutélé which was distributed to the periphery of Liège and Brussels.

Every day, at the start of the channel, the heraldic lion of Luxembourg appeared on the circles symbolising the radio waves and the name Télé-Luxembourg, followed by an image of the Dudelange transmitter, with the voice of Jacques Harvey announcing : "Here is Télé-Luxembourg, channels 7, 21 and 27, Dudelange transmitter, Grand Duchy of Luxembourg.".

On 30 July 1981, the Dudelange Radio Tower was totally destroyed after a collision with a Belgian military aircraft, and RTL Télé Luxembourg was off the air for a few hours, until the back-up systems were up and running.

The French president, François Mitterrand in person authorised TDF to use the former VHF 819 line transmitters of TF1 in Lorraine to relay RTL Télé Luxembourg in colour until the rebuilding of the tower in Dudelange.

A generation of new faces were first seen on the channel: André Torrent, Philippe Goffin, Bibiane Godfroid, Michèle Etzel, Claude Rappé, Anouchka Sikorsky, Jean-Luc Bertrand and Georges Lang.

Under the direction of the new programming director, Jean Stock, a clutch of programmes and presenters were successful: Le Train des jouets, Léo contre tous, Citron Grenadine, Tête à Tête, Stop Star, Le Coffre-fort, Fréquence JLB, Atoukado and many presenters.

In September of the same year, the Belgian channel of RTL Télévision became independent with the launch of RTL-TVi which produced all of its programmes in Brussels.

Deprived of its Belgian audience, and broadcasting to Luxembourg and Lorraine, RTL Télévision was finding great difficulty in positioning itself in the French market.

The need for renewal was felt to be essential, and in 1988, RTL Télévision tried to redynamise itself with small touches, such as modifying its logo and graphics (the appearance of the RTL balloon), and signing stars such as Geneviève Guicheney (from FR3) and launching new faces Agnès Duperrin and Martin Igier who had just graduated from the École Supérieure de Journalisme in Lille to replace those who had joined M6 and RTL-TVI.

RTL TV changed its format due to the new director of programmes, Hugues Durocher, to attract a younger and more urban public.

Films and serials gradually supplemented the traditional programmes and presenters were replaced by a new generation: Agnès Duperrin, Laurent Lespinasse, Katia Schmidt, Thierry Guillaume, Nicolas Albrand, Véronique Buson, Jérôme Anthony, Virginie Schanté, Françoise Gaujour, Fabienne Égal and Charlotte Gomez made their first appearances.

This slogan was repeated on air by presenters at the key shows on the air: Scrabble RTL with Thierry Guillaume and Véronique Buson, 40 minutes with Marylène Bergmann at the start of the evening, the 52-minute weekly RTL Santé presented by Agnès Duperrin, the female magazine F comme Femmes every lunchtime with Véronique Buson and Françoise Gaujour, the video shows of Music Family and Ligne Basket with Jérôme Anthony and Virginie Schanté and Galaxie with Thierry Guillaume, shown for the youth at the end of the afternoon and Wednesday afternoons and the job show Help!.

In 1995, RTL TV marked their 40th anniversary with great ceremony in the grand auditorium of Villa Louvigny and officially renamed the channel RTL9 at the end of the night.

In 2005, RTL9 celebrated 50 years of broadcast with archive footage from between 1955 and 2005, but mostly from the RTL9 period, including a musical spectacular from Olympia in Paris presented by Jean-Luc Bertrand.

Instead, for the last week of December 2005, the programme of Jean-Luc Bertrand, Bienvenue chez vous, was taken over by former stars of the channel: Michèle Etzel, André Torrent, Jean Stock, Georges Lang and Marylène Bergmann, specially brought in to talk about their professional memories of the history of RTL Télévision.

A second event took place at the same time: the return of Marylène Bergmann after nine years away, to take over presenting duties on RTL-TVI, two days per week with her old co-presenter Jean-Luc Bertrand, on Bienvenue chez vous on RTL9 Lorraine.

The first headquarters of Télé-Luxembourg were based at Villa Louvigny in Luxembourg, a building flanked by an eight-storey tower, built in 1956–1957 by the CLT and housing the offices and studios of the channel.

RTL Télévision moved to studios at 3, allée Saint-Symphorien, Metz at the end of 1990 to reach the public of Lorraine, but the final parts of the business remained at Villa Louvigny.

Transmission of RTL9 on the terrestrial UHF SECAM channel 21 from the Dudelange Radio Tower in the south of Luxembourg to the Lorraine region ended just after midnight on 1 January 2011.