This study investigates the use of writing portfolios in improving the accuracy of French immersion students' written French. It emerged from regularly observed notable and repeated errors in many of the author's students' writing (entitled fossilized errors due their resistance to correction). This study reaffirms that students of French immersion habitually make errors in accuracy of language production; that later stage correction of fossilized errors may be possible; that writing portfolios are a suitable second language classroom practice to support improvement in writing; that using questionnaires to guide students towards increased self-awareness and control of their writing is an effective practice, particularly when students are prepared for the task prior to its implementation. (Contains 2 tables.)