Target Language Use in Partner Work

Intermediate French students recently worked in pairs to rewrite Candide, either a single scene or a modernization. There were 3 groups. One group (the most seasoned-upper level Spanish students taking French) did ALL the preparation in French. They suggested a complex rewriting of the play that involved changing the setting to modern day Alabama, Candide to a woman and a lesbian, and the whole thing explored a kind of fallacy theory for a result that was philosophical, substantive and lengthy.

The other two groups handled the project in English with a lot of joking and screwing around thrown in. How to make those groups more like the first? How to incentivize speaking in the target language?

• The course syllabus notes the importance of staying in the TL during pair and group work, but I don't enforce it like I should. I need to circulate and redirect them to English early and often in the semester.
• The grading for such assignments never takes into account HOW the project was planned. I will add that to the guidelines and rubric and attach points to it. It's actually not a bad idea to make them more cognizant of the processes they use to learn anyway. 
• The directions always say both people need to take notes but inevitably only one does. I can build in points for the notes.
• I can build in a reflection that asks them to comment on their language use while preparing the final project. 
• The reflection could include a question about what words or expressions they heard their partner use that they can add to their own repertoire (thus learning from their peers, something to be celebrated)
• I could direct each group to a different location and record themselves, then ask them to listen to themselves and reflect on THAT.