The most common and most likely answer to this crossword clue is the 6 letter word AMIENS
I've seen this crossword clue in The Times
A
M
I
E
N
S
More clues leading to the result AMIENS
- A stag I bagged in French location
- A carriage heading for Scottish cathedral city
- Shakespearean Lord’s appearance in first word of his play
- French city docudrama finally airs
- Relocated in same French city
- French city’s name is translated
- . Area for blokes touring one French city
- Inseam tailored in city near Lille
- French city‘s name is being changed
- Like inhaling air in northern French city
Buddy explains!

The straight part
We know that "cathedral city" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cathedral city = amiens.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.