The most common and most likely answer to this crossword clue is the 8 letter word VOLTAIRE
I've seen this crossword clue in The Daily Telegraph
V
O
L
T
A
I
R
E
More clues leading to the result VOLTAIRE
- Measure of potential fury about a polemical writer
- French writer seen where two rivers merge
- Italian physicist, with anger, becomes prolific essayist
- Critic of French art I love to bits
- Writer shows a measure of potential and a passion
- Satirist displaying anger after dance
- French writer displaying anger after dance
- Famous Frenchman offering bizarre art I love
- French satirist showing anger after dance
- French author exploded to Ravel about one
Buddy explains!

The straight part
We know that "Famous Frenchman" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case famous frenchman = voltaire.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.