(S/E) In Saint-Barthélemy, with the church behind you, take the departmental road on the right (west, towards Beaurepaire).
After the café, take the first lane on the right, which quickly turns into a gravel path.
You will come out onto a small asphalt road (signposted "Boussard"). Continue straight ahead, as if you were continuing on your way. You will pass a first path on the right that leads to a farm.
(1) Take the next path on the right (a yellow sign will guide you). Follow it until you reach a T-junction. Turn left.
When you reach another T-junction, turn right until you reach the next junction.
(2) A faded sign indicates that you are in the Plaine d'Arcieu. Turn left and then quickly turn right onto a grassy path towards Les Revollet (new Plaine d'Arcieu sign).
(3) When you see a pond on your left, you will come to a small tarmac road which you take to the left. Be careful, a little further on, at the end of the meadow, you will take a path on the right at a 45° angle (follow the yellow markings). It is a little hidden.
When you reach a sort of pass, turn left and go up into the woods.
(4) In the woods, you will come to a fork (signposted "Les Revollet"). Take the right-hand branch towards "Le Diaret". You will come out into a field. Ignore the path that joins yours at a 45° angle on the right.
Be careful, when your path reaches the edge of the woods, you must descend to the right. Here too, the path is somewhat hidden.
(5) At the bottom of your path, you will come out onto a road. Make a left/right zigzag. You will very quickly reach a second road where you make another left/right zigzag (if you have had a picnic, take advantage of the recycling bins to lighten your load...). You are now on the Chemin de la Planche, walking alongside the sewage treatment plant's plantations.
(6) You descend to a ford. A sign warns you of the danger this ford may pose in the event of flooding and urges you to turn back in such cases.
If there is no flooding, continue to the bottom of the valley. Your path turns left, then right (in autumn, it is somewhat hidden by leaves). Cross a second ford and climb back up onto the plateau, which you will cross.
(7) In the middle of the plateau, you will see a sign for "Le Diaret". Continue straight ahead until you reach a complex crossroads with a picnic table, strangely placed in the middle of nowhere...
(8) This crossroads is marked by a sign for "Plaine de Braye". Take the first dirt track on your right, which starts at the corner of the small wood. Go down the valley, ignoring anything that may come from the right or left.
(9) You will pass a third ford, also marked as dangerous in case of flooding. Your path makes a chicane to the right, then to the left, to change banks with respect to the stream.
Continue downhill for quite a long way until your path becomes tarmac. Continue downhill, going straight ahead.
(10) You will come out onto the D519 and turn right. This section is safe thanks to the pavement. It is not particularly interesting, but... you have to get back somehow... Continue to the church, where your vehicle will be waiting for you (S/E).