The language view has a selection function
ARTE’s language-change help page says that selecting a language displays programmes available in that language. A film seen while browsing French may therefore be absent after switching to English. That does not by itself mean the programme was removed from every ARTE service or that the viewer’s account failed.
Programme tracks can be checked directly
The broadcaster’s guidance also provides a player-level language control, using a speech-bubble or gear icon depending on the interface. Check the actual offered versions on the programme where available. A navigation language and an audio or subtitle track are related controls, but they do not establish that a translation exists for every video.
The English offer is explicitly a selection
ARTE’s UK help directs viewers to selected English-subtitled programming. Its wider language explanation centres German and French alongside translated selections. When following a recommendation from another language edition, save the original title and programme identifier so the same work can be checked accurately in the English view.
Territory is a separate availability condition
The language-change article warns that not every programme is available in every territory. A title could have English subtitles while still being unavailable at the viewer’s location, or be geographically available in another offered language. Check both conditions before interpreting a blank result or a rights message. Switching a menu is not a method for acquiring different territorial rights.
Make the comparison specific
Record the programme, language view, available player tracks and country. If contacting ARTE, describe whether the title vanished from a language-filtered listing or the video displayed a playback restriction. Those observations answer different questions. They are more useful than assuming that a saved French link guarantees a complete English-subtitled version in the UK.