A mountain area in France (5)
I believe the answer is:
Here is my best explanation:
'a mountain area in france' is the definition.
I can't judge whether this definition defines the answer.
'mountain area in france' is the wordplay.
'mountain' becomes 'alp' (alp is a kind of mountain).
'area in france' becomes 'ha' (short for hectare, unit of area with a French name).
(Other definitions for alpha that I've seen before include "star of utmost brilliance", "Early testing stage for new software or hardware", "Top star", "No.1 in America", "First (class)", "Foremost", "starter", "First-rate", "First, best quality" and "Most prominent star".)