Hi retro gamers ! I , as you can understand , have reached this point in the story line of Deus Ex . And I can't find the damn sword , if you can help me , it would be very thoughtful of you . Please give a video , everything that can help me ...

Thanks in advance !

There's a paper lantern on the ceiling to the right of the elevator door to Maggie Chow's apartment which is actually a door trigger.

Thanks !

I once managed to get soldiers in an adjoining secret room to attack me by attracting their attention simply through running back and forth loudly near the wall. Not a reliable means to get them to open the door, but very amusing.
Other means include coming in through the roof or the maintenance elevator.

One advice thou, you get the sword and use it for a bit, then return it, because I didn't and the game was really easy after that...... :)

Besides the lantern, there are several other ways to get to the sword, and a few secret areas around there too. Happy exploring. :-)

Alternately, if you can get into Versalife before then, but after speaking to her, Maggie will eventually spawn, with the sword, have a short conversation that can be witnessed with another character, and eventually attack you once your cover is blown. Unfortunately, she will at least attempt to use it to attack you, and it is one of the most powerful weapons in the game that NPC's will use. THankfully, she also has about the same level of health as many characters, and will die or go unconcious quickly if you get the drop on her. You'll still need to go to her apartment if you want to upload the sword schematics to both triads, and this will likely lead to a fight with some MJ12 troops, as they are in the hidden section of the apartment building.