Every so often I get an email asking how to find where someone is buried in Paris. I have to break the bad news: there is no central database in for the cemeteries in Paris.
That is, of course, only half true.
There IS a central database BUT you MUST demonstrate a family connection to the deceased before they will release any information to you. Once they have proof of your relationship it can then take up to a month before the request is processed.
If you qualify, then by all means contact the following department (in French please):
Service central des Cimetières
71 rue des Rondeaux
Of course, if you know the name of the cemetery it's easy and simple to learn the grave location; that information is available to anyone. Just contact the cemetery in question (the conservation or office), provide the full name and date of death and they should be able to give you the precise location within the cemetery. It works best if you can go in person, of course. . .