Lightly pound the chicken breasts. Sprinkle both sides with salt and pepper.
In a bowl combine the haricots verts, tomatoes, olive oil, tarragon, garlic, shallots and some salt and pepper. Toss to combine.
Cut four 12-by-16-inch pieces of parchment paper.* Arrange one-quarter of the bean mixture in the center of each parchment, add a splash of white wine, and top with a chicken breast, 1 tablespoon of the butter and one-quarter of the chopped parsley. Meet the short ends at the middle and fold over 1 inch. Fold a few more turns, then fold in the ends to make half-moon shaped packets (sacks). Repeat for the remaining beans, pieces of chicken and parchment paper.
Roast the chicken 25 to 30 minutes and remove from the oven. Serve the chicken packets on plates, then open the parcels carefully and slide the contents out. Discard the paper before eating.
*TIP: buy pre-cut packaged half sheets from any restaurant supply store