France's team is already qualified with its 6 points because only one other team of its group (Australia) is able to finish ahead now. So they don't need a victory against Tunisia for their last match, we can expect them to preserve their strongest players, and to let play the weakest ones, they are unlikely to be offensive in addition. So I think a draw @3.90 is value bet. Even a loss @6.60 could be interesting IMO.
Well, I always look for the most probable outcome and easy guess and then I do my research to find the best odds for this outcome. That is why I go around the under's and the above's a lot. I also rely on the both teams score as well. Just think that in the end, your aim should be to maintain your betting stash and keep the profits. It's my strategy and it pays. So, IMO a value bet would be under 2,5 goals or the draw at half time.