In many countries, like France, rent increases may not be in excess of inflationary increases in the cost of living. Other places have various forms of rent control. In places like Monaco, where there are no controls, you can only try to have a calm discussion with the landlord to show him that he is attempting to charge you more than the market rate for similar rentals.
If you are getting a bargain deal —even with the increased rents — it is better to keep your mouth shut and go along with the increase.
Your alternative is to either move, rent elsewhere, or buy a place of your own.
As to why you are being singled out for increases, based on my own experiences with tenants,
Are you more of a pain in the butt than the others? Possibly you don’t even realize it!
Maybe you are late with rents. Maybe you generate complaints from neighbors because of parties or otherwise. Maybe you are always demanding stuff like replacement sinks, stoves, fridges, washing machines, etc.
Do you have annoying pets like barking dogs, smelly cats?
Are you a trouble maker complaining about or reporting your landlord to the health department or bureaucracy?
In my own land-lording days,
I raised rents on tenants I wanted to get rid of because I hoped they would move.
On my best tenants, I’d never raise rents because I was happy to have them and keep them. A landlord can discriminate against tenants as long as it is not because of race, religion, etc.