Park along the pavement at the top of Rue Robert Blum (don't forget to apply the handbrake as it's on a slope).
(S/E) Go up the path at the end of the street. It turns right 200 m further on.
Keep right after the house. The path continues through the forest until you reach a clearing where, on the left, a little higher up, you can see the Fontaine Rouge, where we will stop on the way back.
Continue along the path opposite and walk alongside old orchards and gardens that are now abandoned.
(1) At Chemin de Mousson (small paved road), cross it and take the path opposite, on the left, for about 300 m, then descend to the right.
At the bottom, turn left, walk along the gardens and go back up into the forest. Follow this path until you find another path that climbs steeply at a 90° angle to the left (see practical information).
(2) Go up this road. At the top, you will arrive in fields with a view of the castle. Turn right.
Go around the fields and you will come to a small paved path (Chemin du Haidoin).
At the small road, continue straight ahead (Chemin d'Urtal). Pass the remains of the high gate (known as the Urtal gate), then take the street on the left (Rue des Templiers) and pass the ruins of the Templar church.
At the end of the bend on the right, go up the path on the left which leads to the ruins of Mousson Castle.
(3) Enter through a gap in the surrounding wall.
After walking around the castle terrace, you can look south to see the meandering Moselle and the ponds dug by men in the upper river bed to extract sand and gravel.
(4) Go back down through the passageway facing south in the surrounding wall, which is supported by scaffolding. Turn right immediately.
The path at the foot of the wall is a little dangerous. It ends 100 metres further on, on the left, at a staircase made of railway sleepers, which are very stable but slippery in wet weather.
At the bottom of the steps, the path continues to the right for 200 m. Here, on the right, is the memorial to American General Edmund Searby, who fell on 14 September 1944 during a German counter-attack, and on the left, another set of steps made of metal beams, which you should take. At the bottom on the right, continue to the war memorial and descend towards the car park.
There, take the road on the left and then left again (Chemin de Mousson) to find a pretty fountain 400m further down (under restoration in January 2014) and 300m further down, the path you took on the way up.
(1), take it on the right towards the red fountain.
(5) This time, at the clearing, go up towards the red fountain and then take the small path that enters the forest on the left. Follow it downhill until you reach the car (S/E).

, contrary to popular belief about the flatness of Lorraine!
This hike is NOT easy, as the description says. When I see 5 km and easy, I decide to do it with my 8-year-old children or as a short detour on the way out of town; but beware, this is a real MEDIUM+ level hike that requires good shoes, experience and good physical condition. When your legs are not trained, the slopes are very hard. The path, especially in the second part, is not maintained. The vegetation is very tall, almost impenetrable, so you can't see the trail. There are difficult wooden steps leading up to the castle. I am 1.75 m tall and the height of the steps (covered by plants) was just manageable for my legs, and there are a lot of them. At the top, along the wall, there is no path and you have to be careful not to fall. After the castle, between points 4 and 2, the descent/slope is so steep that you have to hold on to the trees where there are any. This hike should really be classified as medium to difficult, not easy at all, I don't understand.
If you are in good shape and you like challenges, you will enjoy this hike. After a long slope, you will see Pont-à-Mousson and all the fields and nature around it. During the hike, you will be surprised at how much history there is to see in this small area. The hike is worth it, but only if you consider walking a bit of a sport or a challenge.