I have tried for a long time to get onto the Ossuaire in The Saboteur, but I don't find any place to climb it. The yellow lights have not been helpful either. How do I reach the scenic spot?
Below is the walk-through for the mission that involves L'Ossusaire. However, in this mission it is not a requirement to be on the roof. Also included is steps to obtain all the diffecult Scenic Spots.
Behind The Convent Gate (optional mission)
Talk with Wilcox in the church to start this mission. He wants you to blow up an old abbey.
Drive to L'Ossuaire, its on the other side of the map east of Lorainne.
You need to destroy several targets marked around the abbey. You'll want to take out the guy in the tower by the gate to grab his uniform, makes sneaking around inside the abbey easier.Blow up each terminal, and don't forget to collect the post card on the floor behind the right side machine gun before you blow that radio station.
Taken from here.
However, to find all the Scenic Spots, the below is how to get to them.
There are hundreds of freeplay objectives around the map to destroy. These range from searchlights to AA Guns. For each one destroyed you will be paid a small amount of contraband. Contraband is required to buy weapons and ammunition. You need to buy maps to show you where all the targets are.
You can complete the free play objectives at anytime even during missions.
06.01 - Scenic Spots
I have listed how to get some of the scenic spots that I found tricky to get and how to get to them. The way you get up them on each building look for the yellow lights they usually mark the way.
Scenic Spots (Paris 1)
1) Top of building in La Halles You need to climb up to the western side. On the triangle roof face south and run jump up the wall. Alternatively just climb the ladder around the corner. You can climb to the top easily from here.
2) Top of circular building in La Halles When you get the one on the bigger building use the wire to slide across to the other.
3) top of building in La Bourse
Climb up the drainpipe in the southeast corner of the building. About
halfway up Jump off onto the platforms to the left. Face south and running
jump away from the building and you'll grab some planks. Pull yourself up.
Go along planks and up the ladder. Jump up to the next set of planks.
4) Building In Opera District Use the wire on the building to the west to slide over. Move right slightly then climb up. Face away from the building jump away from the building then quickly back and you'll be on the roof. This bit can be tricky but once you've done it then it plain sailing.
1) Climb the pipe near the door up to the roof
1) Climb on top of house and face tower. Jump at the window on the tower and climb up.
1) Top Of Lighthouse - use the windows to head up in an clockwise circle. 2) Top of castle - climb up inner bell tower in courtyard in the middle of the castle in the far north west of the map. Once inside the bell tower climb up the inside wall in the north east of the tower to get to the top.
1) South of Champs Elysees, climb up the ladder on the south west corner of the "D" shaped building. Jump up and shimmy right and you should be able to climb up to the walkway on your right. Climb up the small ladder again and its near the guard tower.
2) South of Champs Elysees, use zipline from roof of 2 above. Climb one of the square structure on the corner of the building and running jump towards the arch. You should be able to run up to the platform and climb up.
3) Trocadero - use the scaffolding and windows to climb to the roof. Ascend a big ladder then turn around and climb a massive drainpipe. Jump across to ledge then climb up.
4) "A" shaped building south of opera district text. Approach from the north and you should be able to climb the outside easily. Once on roof head to the spot in the centre of the building.
5) Big coliseum style building just south of the Gare Saint Lazarre. Look for the wire from the building to the west. Climb that building and cross the wire. Drop and press right to grab the walkway and then pull yourself up. Jump up to the ladder and you're on the roof.
6) Isle De La Cite (east building) - Grab a Nazi uniform and swim in from Paris zone 3. Climb up the ladder and enter the area. Go to the north side of the big building. Climb up the small scaffolding then onto the pointed roof. Ascend the drainpipe and climb up onto a platform before climbing up another drainpipe. Pull yourself up to the roof and you're there.
7) Gare Saint Lazarre - on the building behind is a connecting walkway you need to use that to cross to the building with the spot. Use the small ledges along the station building. The last jump up can be tricky you have to do a running jump up the building then press right to grab the ledge near the walkway. Pull yourself up on the roof and its easy from here.
1) Isle De La Cite (west building) - along the inside northern wall is some scaffolding, use this to climb up. Then climb the wall and its on the roof.
2) Isle De La Cite (west building) - along the outside corner of the wall there
is a row of lights. Climb up the post on the corner and up to the ledge.
3) Montparnasse far north near check point. Go around the back of the building and climb up the door in the bit sticking out. Climb onto to the main building and shimmer left or right to the corner then pull yourself up.
4) Montparnasse far north near check point. Climb up the build building.
5) Top of building near Paris Saint Germain. Use the ladder on the south side
of building to get to the first roof. Head west and climb up the next
ladder. Go to the north side of the building and there is another ladder
up to the next roof. Then there is a final set of scaffolding to climb.
6) Top of the Eiffel Tower. You need to use the lift to get to the first level. A second lift will take you to the next level. You then need to use the stairs and ladders to get to the summit.
7) Church north of Saint Germain. Climb up the low roof of the north side.
8) Big building south west of Latin quarter. Climb up the scaffolding on the
south side of building. Jump to the drainpipe and pull yourself up.
9) Building north east of Eiffel Tower. Look on the east side of the building for some lights and climb up the windows to the roof. Running jump east to the planks opposite. Follow the ledge around to the scaffolding and climb the ladder. Climb up to the next level then use the window to get to the plank in the corner of the building. Do a running jump up the wall then pull yourself up onto the roof. Look for the window with the wooden ramp in front. Climb onto the ledge then use the left hand side of the window to climb up. Grab the top of the window. Shimmer across to the ladder and climb up. Then jump up and climb up the remaining wall to get to the top of the building. Spot is on the south side.
10) Directly east of Eiffel Tower. On the south side of the building you'll
see a light. You should be able to climb up the middle of the door.
11) This in on the big ferris wheel in the fairground. You can use the outer leg to run up to the centre of the ferris wheel. Jump out and grab one of the spokes of the wheel. Climb and pull yourself up until you can't go any higher. Then you can make your way along the edge other wheel so you can make your way up to the top. When you get there hang on the outside and jump up and you'll pull yourself level with the final spot inside the car.
Taken from here.
There is no scenic spot on top of the Ossuaire. (I was misled by the existence of yellow lights, and I thought that every major building in the game has a scenic spot on top of it, because the others do, and I had not bought the map of targets yet.)