This paper describes our approach to the 2006 Adhoc Monolingual Information Retrieval run for French. The goal of our experiment was to compare the performance of a proposed statistical stemmer with that of a rule-based stemmer, specifically the French version of Porter's stemmer. The statistical stemming approach is based on lexicon clustering, using a novel string distance measure. We submitted three official runs, besides a baseline run that uses no stemming. The results show that stemming significantly improves retrieval performance (as expected) by about 9-10%, and the performance of the statistical stemmer is comparable with that of the rule-based stemmer. Categories and Subject Descriptors H.3 [Information Storage and Retrieval]: H.3.1 Content Analysis and Indexing; H.3.3 Information Search and Retrieval; H.3.4 Systems and Software; H.3.7 Digital Libraries; H.2.3 [Database Managment]: Languages--Query Languages General Terms Performance, Experimentation Keywords statistica...