Open the combined menu for the actual programme
The publisher places Audio and Subtitles in the video settings near the lower right of the player. Open it on the episode being watched and inspect both the audio and text choices. A French-language interface is not evidence that every possible French accessibility rendition exists. RTBF says audio description and deaf/hard-of-hearing subtitles are offered for some programmes, not universally.
Choose narration through the audio option
Where offered, Français with Audio description selects narration of visual information for viewers who need it. The help says returning to ordinary Français turns that description off. This is an audio choice. If an extra narrator is heard, look at that selected track before assuming the programme itself acquired an unexplained second soundtrack or that a subtitle setting must be responsible.
Choose the intended French text track
The menu separately distinguishes French subtitles and the French deaf-and-hard-of-hearing option. Select the latter when that is the viewing requirement, rather than assuming a plain language label provides identical information about relevant sounds. None removes subtitles according to the published control. Keep the audio choice fixed while comparing text, so changing two settings at once does not obscure which one affected the result.
Recognise a genuine missing-language limitation
RTBF says that when French is the only audio offered, the fiction was not supplied as a multilingual version when the rights were bought. Changing the interface language cannot create an absent original-language track. Record the exact item and available choices if clarification is needed. This workflow identifies the publisher’s labels; it does not certify translation quality or report a tested account.
Questions, answered
Does Français always mean the same option?
No. Read whether it describes ordinary audio, audio description or an SDH subtitle track.
Can changing interface language add an absent audio track?
No such feature is established by the cited help.