Page 179, The Taste of America gives the following notes.

"... in France, French women have made pouletau vinaigre for centuries. The dish will vaty slightly with regional differences in the chicken, the type of vinegar, the aromatics and the fat used in the saute'eing. One of our prized recipes comes comes from from an old woman in the causses of the Quercy who saute'ed the chicken in goose fat with a clove or two of garlic and simply sprinkled verjus (unripe grape juice) on towards the last. If it were an older bird, she explained, she would put the verjus in right after the initial browning, thus demonstrating the origin of the dish; vinegar and similar acids have a tenderizing effect. She warned against too much; just enough to give "that little tart taste." 

    The ingredients below are my guesses....  There is a variation on this to be found here in the same book

1. 1 small chicken in parts - I assume.
2. Butter or goose fat sufficient for sauteeing.
3. Vinegar sufficient for flavoring.
4. Herbs as you like and available. Parsley for sure.

1. Sautee chicken pieces until brown both sides.
2. Add herbs and baste with pan juices and herbs as chicken cooks through
3. Towards end of process, sprinkle with vinegar and turn in juices to coat.
4. Remove chicken and cook down pan juices and pour over/around chicken.
5. The pan could be degreased before the aromatics are added. The reduced pan juices could be thickened with cold butter. I'm guessing here.