Building manager came into my unit to remove my christmas decorations

l live in alberta and i rent through a building management company. We were told we can only have christmas decorations up until January 12. We received an email from the management saying that they will be doing a building walk through to remove all decorations up after the 12th. I assumed this meant doormats, door wreaths etc. I came home today to find they entered my apartment and removed my decorations such as my mini christmas tree and all my sentimental ornaments. How could this possibly be legal? Theres nothing about this in my lease. They told us we can get our decorations back from them but its unacceptable that they took them in the first place... why?!? Why does it even matter? Im baffled by this and i dont believe it is legal but i have no idea since they vaguely warned us in the email i guess.

UPDATE 1: Thank you everyone for the advice! I have filed a complaint with the RTDRS and the building owner. I havent contacted police yet because i am planning to thoroughly look through my decorations when i get them back tomorrow to make sure i have all my information straight if I plan to file a report. I am hoping that my complaints will get my building manager fired because I do really love my apartment aside from this, it is a great location for me and a fair price compared to skyrocketing rent across calgary especially in the more urban areas. I know for a fact if i were to take legal action and he somehow wasnt fired, or one of the other managers takes over, i would definitely be scrutinized for causing trouble and probably not offered a new lease after my 12 months. The management for this apartment has been very difficult, and they are very controlling and unforgiving hence why i have gone out of my way to not cause trouble so far. It will definitely help my confidence if I can get some of my neighbours to file reports also. Ill keep you all updated on what happens next !

UPDATE 2: I received another email today saying this

“Hello All, We have noticed that a lot of unit doors are quite dirty from the hallway side. It is the responsibility of the residents to keep the doors clean on the inside and the outside. Much of issues noted are handprints near the handle and also on the lower parts of the doors where people have used their feet to assist in opening the unit doors. We want to keep all of our buildings clean and upkept for the residents. We want all the residents to be proud of their homes. Please note that we will be conducting building walks on January 17th, fines could be assessed to residents that choose to not address this concern.”

The fact that they said inside and outside leads me to believe they are planning to enter units again on the 17th