Bastille Sewers

[Sul]

When passing the Marais district, there is one area connected by bridges, to another district, which then leads to Place Royal.

These bridges have a sort of canal below them, which is connected here and there with sewers. There's one locked door, that opens from the other side. How do I access that area? I flipped the level upside under. Eventually I decided to cheat and use free camera to search for an entrance, but I found none. There's a huge canal starting near the Bastille, which leads to a district, where one sewer opens to the front yard of an estate, this canal I saw is what leads to that locked gate in the canal below the bridges in the Marais. To get to the point; how do I access that area?

[Narcissistic Cannibal]

Several people, me included, have created similar topics. Most likely, it's a DLC area.
You might check the video in this topic (didn't watch it myself to avoid spoilers):
https://steamcommunity.com/app/1283400/discussions/0/3492004456590138642/

[marshtackie364]

Jump into the canal, go to end where locked gate is. Just to the right is a weak wall you can break through (you need ramming ability to do this).