I’ve gone twice, the first time, it was awesome! I was with two friends, we roamed and checked out basically every street. I even got to put a lock on the lock bridge for my partner at the time. Everyone was friendly and 2 of us spoke French so that helped a ton.
The second time I went was a few years after. The terrorist attacks had happened and the experience was not as great. The Eiffel tower is now gated and patrolled, you need had to get in lines and wait to get up close. They also had taken down the lock bridge (I was still with the same partner). It was still a good experience for sure, the vibe was different though.
Paris at night is beautiful, though remember that it is still a city, so treat it as such.