At a French table a simple salad will usually be served as the main course finishes. It is completely acceptable to add the leaves to your gravy remains and eat away. In fact it would not be considered de rigueur to eat the salad with your hot food, and the crunchy leaves make a great contrast to the meaty juices.
Don't dress the leaves, but offer little bottles of oil and vinegar on the table so guests can add to the salad as they prefer.
As the salad finishes, a cheese will be offered. This is to enjoy with the last remains of the baguette and main course wine. The French would serve just one variety of a very beautiful cheese, not a pot pouri of cheeses like Kiwis do. So serve your favourite in a limited quantity.