Depending on where you go, I would get one of those international wall adapters and run the AC>DC wallwart to run the unit (at home). I would also inquire with Tascam about getting a Euro Wall Wart. I have to believe they have one in a warehouse somewhere, or they may tell you the specs you need to buy one off of Ebay, etc.
In the field, I would find the French equivalent of Radio Shack or Batteries Plus and ask them about rechargables, etc. They should be able to supply you with a DC supply that will run the unit, that can be charged at home, and is portable. Think "RC Car batteries", a good hobby shop may fit the bill.
I thought I read you will be in Mali??? Good luck!!! I'd love to go tape the Festival in the Desert, I'm into Khaira D'Arby and Tinariwen right now... Make sure you bring plenty of sand-protection. The BBC special I saw about it mentioned how the sand got everywhere including inside their TV equipment...
http://www.festival-au-desert.org/Bring back good stories and good tapes!
Terry