But...I still have an accent. No one would ever mistake me for a French person. I often get comments about my accent, and I think some people are surprised that I can speak good French but haven't got rid of my British accent.
On the whole, even very good speakers of a foreign language, who have been living in a foreign country and speaking that language every day for 30 years will still not have a totally "perfect" accent.
French speakers who speak excellent English for example, may still mispronounce certain vowels, perhaps the h will occasionally disappear, or the th will be different. They won't sound like a French speaker anymore - people will have to ask "where are you from?" - but they won't sound like a native Anglophone either. It will be a mystery accent.
Of course your accent will improve, especially if you work at it, but it is totally normal to still have your accent, even after 25 years. It is charming and it is you.
And here is some unusual news about accents: