When French write American English and when Americans write about French institutions, rather. Generally it's "centre" in British and Canadian English.
Sincere question from an American: can you explain why er and re make different sounds at the end of a word than everywhere else? like "read" or "redo" or "terror".
It is common in languages that phonemes (groups of letters making a single sound) are pronounced differently depending in where in a word they occur. At the start of a word, they may get more emphasis and that can chance the pronunciation. At the end of the word, there is a tendency to drop emphasis as you prepare to speak the next word. That causes a phoneme like “er” to sound like “ur” at the ends of words.
French regularly confuse "er" for "re" when they write english, but so do the english speaking word (center is writter centre and pronounced centre).