The most common and most likely answer to this crossword clue is the 8 letter word CHARTRES
I've seen this crossword clue in Independent
C
H
A
R
T
R
E
S
More clues leading to the result CHARTRES
- Cathedral maps, about to be introduced
- Orchestra, heading off to play in cathedral
- Plan brief residence in French city
- Somewhere in France that's cleaner — and very French!
- French city map despatched again with 50% missing
- Cathedral plans to include religious education
- Engineers opening plans for cathedral
- Plans to hold religious education in French cathedral
- Plans to accept scripture lessons in cathedral
- French city map on centre of dresser
Buddy explains!

The straight part
We know that "cathedral" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cathedral = chartres.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.