World number 11 Murray, seeded fourth in the indoor event, will face Croatia's Mario Ancic in Sunday's final.
Ancic, who dropped out of the top 100 after missing most of last season with glandular fever, knocked out sixth seed Marcos Baghdatis 6-4 6-2 in the other semi-final.
After breaking his opponent in the first game and again in the fifth, Murray underlined his determination by winning his last service game of the first set to love.
Playing close to perfection, Murray captured Mathieu's serve again in the third game of the second set.
Murray stayed on top with another break in the seventh game and then served for the match, earning three match points with an ace. Mathieu survived the first but netted a backhand on the second to bow out after 62 minutes.
"I played really well," said Murray, who will play his second final this year after Doha, where he won the title last month.
"It was probably one of my best matches this year," he added. "My serve was strong and my plan to force him to take the net worked perfectly."
The other semi-final was tighter at first, both players holding serve until Ancic broke Baghdatis in the ninth game before wrapping up the first set on his service game.
Ancic, a losing finalist in Marseille in 2006, stepped up a gear in the second set, relying on booming serves to cruise to victory.
Murray and Ancic have met once before, in Auckland in 2006. Ancic won 6-3 7-6.
(Reporting by Eric Salliot, writing by Patrick Vignal in Paris, editing by Alan Baldwin)
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