Here is the link to a web site where you can find and print a Plan Cadastral. It is the official web site from the French government.
You can either enter the Cadastral References if you know them or the full address.
If you don't know them, look for your deeds and you will find them on page 2 or 3. You are looking for a letter and one/or several numbers, ie Section A, No 123).
You will need a Plan Cadastral if you apply for planning (for renovation or new builds) or if you sell your property in France.