That's the famed regulation 101. Staff can also choose not to speak in English with you, if they feel so inclined, or don't speak English. To be fair to the Quebecois, English is rarely used on the Paris Metro as well, and you will probably struggle to find an English speaking staff member
Well, to be fair to the Paris metro, there are many plurilingual signs and announcements, but the degree of plurilingualism not always consistent.
Bizarrely, signs such as “Sortie” or “Correspondance” (“exit” and “transfer”) are only in French.
TVMs display French, English, and I think other languages too.
However, many signs are written in three or four languages (including really very specific signs such as “caution, trains may brake hard” or “alarm - penalty for misuse”) and on lines with automated announcements (*), they are provided in several languages - French, English, and depending on the lines a mix of Spanish, Italian, German, Chinese and Japanese. Automated platform announcements (about closed stations for example) are also at least made in two languages.
You will not need to struggle THAT much to find a staff member conversant enough in English to meet the needs of a foreign customer. (However you may need to struggle to find a staff member anyway, especially if you use the level of staffing of the London Underground as a benchmark). I know that the command of English of the average Frenchman is imperfect, but let’s not exaggerate.
(*) compared to the London Underground, in-train announcements in the Paris metro are very laconic. The name of the next station is uttered twice (with two different intonations), there are reminders at stations with a significant gap between the train and the platform, at terminus or junction stations (line 13), and a handful of other messages (“please get off the train on the left” - line 14 at Gare de Lyon, “beware of pickpockets” - almost everywhere).