The apartment was full of chemical air fresheners. It had sachets in the closet, scented popurrí in bowls, a chemically scented plug in, strongly scented trash bags, and a battery operated gadget in the bathroom dispensing a toxic blast every second. After we checked in my husband started wheezing and I developed an immediate headache. So, we rounded up all the stuff listed above and stashed it away. That was when we noticed the sewer gas smell in the bathroom. Obviously they have a sewer gas problem and were trying to hide it.
It took us a couple of days to rid the apartment of the noxious perfume. (And our allergy symptoms). We then made a “makeshift plug” for the shower drain to keep the gas from escaping. We used a plastic bag full of water and it stopped most of the stench.
The apartment is in a beautiful old building and I understand the problem of plumbing in old buildings. I have experienced this in Central and South America but they use drain plugs.