The river bank may be quite crowded, so it isn't that the area is unsafe, crime wise, it is more that people get quite drunk on NYE and then shoot off lots of fireworks. This itself can be scary, but it is happening all over Germany.

If I had to pick a hotel, I would go for the Ibis on the Friedensbruche. This area is less crowded with firework shooters, but you still get a good view. Plus it sits right on the river. Ask if you can get a room with a view. That way, if it is too cold, or the smoke from the fireworks gets to be too much for your wife, you can watch from insider.

The Adina is also a good location, only a block from the river and it has good views.

An alternative thing to do, is to arrange to go to a party in one of the hotels that has higher floors, like the Fleming City Deluxe, Eurotheum, the Intercontinental, or perhaps the Marriott or Hilton.

The area around the HBF is also not an unsafe area. Only one area, 3 blocks by 3 blocks is the red light zone and unless you go walking through there, you will probably never know it is there. The business pretty much stays in this contained area.

Fireworks pretty much will be going off for at least 45 minutes after midnight. They are legal to buy here, the 3 days before NYE. These are good fireworks too, some of them quite spectacular and you can tell that people gave a lot of money out for them.

As it is very close to the river I´ll go for the Ibis, thank you very much!!!!