From Sahih Bukhari (Hadith 1587):
Narrated Ibn `Abbas:On the Day of the Conquest of Mecca, Allah's Messenger (ﷺ) said, "Allah has made this town a sanctuary. Its thorny bushes should not be cut, its game should not be chased, and its fallen things should not be picked up except by one who would announce it publicly
Reference: Bukhari 1587