We analyze voicing in sequences of obstruents with French as L1 and German as L2, languages characterized by strong differences in the voicing dimension, including assimilation direction. To that purpose, we study the realizations of two sequences of obstruents, where the first consonant, in final position, is fortis, and the second consonant, in initial position is either a lenis stop or a lenis fricative. These sequences lead to a possible anticipation of voicing in French, a direction not allowed in German given German phonetics and phonology. Highly variable realizations are observed: progressive and regressive assimilations, and absence of assimilation, often accompanied by an unexpected pause. Results show that French learners tend to perform better when the consonant is a stop than a fricative. Results are discussed as a function of French learners' mastering of German (final voicelessness, stop voicing, as well as phonological system).