Icon SportTi'i Paulo' s effort just 11 minutes from the end of the match was the only try in a tense affair, and settled the nerves for Clermont, who can be caught by Toulouse when they host Brive on Saturday.
Montpellier fought bravely, adding three penalties in the first 55 minutes to stay within three points of their hosts.
But Morgan Parra booted over a penalty on the hour to stretch Clermont's advantage, and added the conversion to his Samoan team-mate's try to settle the contest.
