Find the Sewer Exit
When the server bridge begins you'll want to run forward and climb the only ladder available, exiting the sewer and completing your first objective.
Reach the Eiffel Tower
You need to avoid the search lights as you're making your way toward the Eiffel Tower. To do this, sweep around the left, passing up and over the tank. Go through the hole in the fence and jump up on the wall to complete your objective.
Climb the Eiffel Tower
Start climbing the base of the Eiffel Tower, making sure to avoid any search lights that are sweeping the area around you. If you have to, drop back down or even move to the side, but be patient and make sure that you ascend the tower using the cover of darkness. When you reach a narrow ledge, move forward until a cut scene progresses things forward.
Reach the First Platform
Walk across the beam and jump to the platform a few feet away. From there, move to your left, making your way to a second platform and passing over it before jumping to a fence like wall. It's a very similar experience to when you first began to climb the tower; just move up slowly while making sure to avoid any search lights in the area.
Climb to the Top of the Eiffel Tower
Move forward and climb up over the Restaurant sign directly in front of you, then turn left and begin your ascension further on up. This part is only made tricky by the electrified portions of the fence, but in reality they are just like the search lights. Avoid them at all costs and make your way up the tower, hopping onto a ladder when you get near the top.
You'll now find yourself on one of the platforms, and as you make your way around it in a counterclockwise direction a plane will begin shooting at you. Take cover, then when there is a break in the assault make your way to the gun along the railing. Follow the on-screen instructions to take cover when it attacks, then emerge and engage it when it resets for another run.
Continue to make your way up the tower, climbing up some debris and jumping over to a blimp that's hovering nearby. After a short cut scene, run across a rope to get back to the tower, then use a lift to see yourself delivered to an area with more search lights. Once again, climb your way up while you avoid being spotted at all costs. When you arrive at a second platform and machine gun, your objective will finally be complete.
Destroy the Planes
This isn't much different than the first time you had to shoot down a plane. The only thing you have to worry about is a second one that has joined the attack. Our strategy was to let them both make their attacks while we stayed in cover, then pop out and shoot the second one as it was resetting for another run. You can usually get away with engaging them for a second after they start shooting at you, but it's a dangerous and very unnecessary game. Just take them out when they aren't facing you.
Escape Through the Portal
The rest is fairly simple. Just continue to climb until you reach the very tip of the Eiffel Tower, then take a leap of faith when your instructor tells you to do so. That will bring the server bridge to an end.