The wall smells chalky/stone-like - clothes too - need advice

I once moved into a renovated old apartment where I had a similar issue. The smell also settled into my clothes and was very unpleasant. It took about 6 months, if not longer, for it to go away.

The apartment had apparently been quite neglected before. Possibly the walls themselves, even after renovation, reflected what they had absorbed over the previous decades. Together with the renovation odors (actually "stony"), it was an unpleasant combination. Maybe that could have been done better during the renovation.

My advice would be to heat well, ventilate, and keep an eye on the humidity. Or just call in a biologist.

I also considered removing the wallpaper and just painting the bare wall. But then I decided against it when I saw the colorful walls under the wallpaper.

Wallpaper also holds odors very well. If I understand you correctly, they are from the previous owner and already old?

Just under 60% humidity is not normal at the current outside temperatures either. It should be significantly lower, I can hardly get over 40% right now (also in an old building). Ventilate more, heat more.

The previous tenants were a young family with two children. I wrote to them again yesterday; they were aware of a musty smell after not ventilating for a long time, which is rather normal. They do not know of any smell in the clothes. I would rather claim that they did not notice it because I already found their own smell strange during the apartment viewing.

Regarding humidity: in the living room there are still the old double casement wooden windows, where the humidity is always at 52, at the back near the new windows somewhat higher. The dehumidifier, for example, always shows a humidity level 5-8% lower than my hygrometers.

Is there any masonry that can actually smell like that or is it rather something "unhealthy"?

In the room where the clothes racks are, I don't even smell it. Only outside and on the clothes. And I simply find that very disturbing or disgusting. In another room, I also smell it, but my boyfriend does not. However, I would actually accuse him of having a not very good sense of smell.

Maybe switching detergents would be worth a try. I find it illogical that the clothes are supposed to smell of something you don't even detect in the room where the clothes are hanging. But I repeat myself: In a heated old building, the humidity should not exceed 40% at the current outdoor temperatures. Unless laundry is being dried or active humidification measures are taken. I would also try airing out more often. The wall itself shouldn't (noticeably) smell. Either there must be moisture or some weird paint / whatever involved.

It cannot be the detergent, I have been using it for decades. And recently also a dryer. When the laundry is in the closet, it also smells like laundry. The laundry that was dried in the mentioned rooms (even before the dryer) or hangs on the clothes racks smells chalky/steny. And I can also smell the odor when I smell the walls.