السلام عليكم ورحمة الله وبركاته , i have an urgent question. My sister ist getting married and its tradition for the man to come to the house to ask the father for the womans hand. People will be there, apartment is small. Is men and women sitting at different sides and not interacting sufficient?

If there is no free mixing, then this is allowed. There should be: 1. No showing of awrahs 2. No sitting together, mingling, or chit-chatting They can also put something to separate the men and the women so they aren't seeing each other, such as curtains, partitions, or something similar. Allah Subhanahu Wa Ta-ala knows best.