Working in France, even with the large consulting firms like AT Kearney, Bain, BCG etc you have to speak & write French VERY WELL. I guess that exceptions would be made for certain people that have expertise in very special areas that cannot be found in France. The economic downturn have forced consulting companies in France to reduce staff and in France this is very expensive. This means that your competition comes from a large number of french consultants made redundant, often from les grandes écoles. Additionally, salaries in France (especially from entry-level to associate (Post MBA) level is lower than, say UK. A typical Business Analyst with BCG, Bain, ATKearney etc will earn around EUR35000 and an Associate around EUR60-65000 - there are other benefits that may be added such as pension payments, profit share and bonus that add 10-30% to the salary but in todays economy the market is tough with many candidates and few positions.
Unless your French is really good, you may find it difficult to find a job in France but one should never say never. I think that your best opportunity would be to focus on the large international consulting firms having projects abroad as well as in France. However, you may also find that smaller specialist consulting firms may be interested in broadening their international profile or competencies.
Best of luck