The most common and most likely answer to this crossword clue is the 7 letter word BOURRÉE
I've seen this crossword clue in The Guardian
B
O
U
R
R
Ă
‰
E
Buddy explains!

The straight part
We know that "French dance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case french dance = bourrÉe.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.
What does BOURRÉE mean?
BOURRÉE noun- A baroque dance of French origin, common in Auvergne and Biscay in Spain in the 17th century.
- A piece of music in character with such a dance.