Parking is available on Rue du Château in La Petite-Pierre, near the Tourist Office.
(S/E) Go down Rue du Château towards the castle until you reach the church.
(1) At the bottom of the street, pass to the left of the back of the church and go down the steps just to the left of a fire hydrant. Follow the path down towards the Ancien Lavoir.
(2) At the fork in the road, keep left.
(3) When you reach a small road (Rue du Lavoir), turn left and pass the old wash house restored by Mrs Jung. G in memory of the washerwomen of La Petite Pierre, then turn right onto the path marked with a yellow rectangle (GR®®532). Follow this path uphill to the Rocher Blanc. The slope is quite steep but manageable. At Rocher Blanc, there is a beautiful view of La Petite Pierre.
(4) From the rock, retrace your steps and continue up the yellow rectangle path for about 50 metres. Turn left onto the flat path marked with a yellow-white-yellow rectangle. This joins a carriage road. Continue along the road.
(5) Leave the road by taking the path on the left towards the Grand Chêne (keep your eyes peeled, as the sign on the left is quite discreet). A little further on, a signpost indicates the location of the Grand Chêne, a remarkable tree located 15 metres below. Continue along the path.
(6) At the end of the path, turn left onto the path marked with a yellow cross towards the Rocher des Païens. This leads to a track, which you take to the left. After about 400 metres, leave the track and take the path on the right, still marked with a yellow cross. You will pass over the Rocher des Païens, which you go around by descending to the right until you reach a junction.
(7) At this intersection, turn completely left onto the path marked with a red diamond. Pass in front of the Rocher des Païens and continue downhill on the path marked with a red diamond.
(8) When you reach a carriageway, turn right and follow the red signpost until you reach Kohlthalerhof (the last hundred metres are on the red GR®5 route). Follow the road to La Petite-Pierre (D178) for just over 100 metres.
(9) Then turn right onto the small road towards Imsthal.
(10) After 50 metres, take the path on the right, marked with a yellow triangle. It runs alongside the road and allows you to hike safely. It joins the road just before the Imsthal estate.
(11) After the Auberge d'Imsthal, leave the yellow diamond path on your right and follow the red-white-red rectangle path on your left to the old Loosthal forest house.
(12) At the Loosthal crossroads, turn left for a few metres, then take the path on the right marked with a blue rectangle (GR®®531), which runs alongside the forest road.
(13) Further on, leave theGR®®531(blue rectangle) on your right and continue straight ahead along the red triangle path. At a fork, keep to your right until you reach the edge of a clearing. Cross the clearing diagonally to get closer to the road.
(14) At the end of a clearing, after rejoining the red triangle for a short distance, cross the road (D134) carefully and take the red triangle-marked path on the left towards Imsthal.
(15) At the end of the valley, turn right onto the path marked with a yellow diamond and head uphill towards La Petite-Pierre.
(16) Near La Petite Pierre, leave the path marked with a yellow diamond and continue straight ahead. Then turn right to follow the wooden ramp and then the stairs that lead up to the Maison des Païens. Cross the building to exit onto the street and turn left towards the castle and the car park (S/E).

Nice walk. Perhaps a shelter would be useful halfway along the route in case of bad weather.