1-Severe punishment for whoever intends evil in the sacred precincts, whether he performs it or not.
Allah, the Most High, said: “And whoever inclines to Ilhad (evil actions) therein or to do wrong, we shall cause him to taste a painful torment.” (Al-Hajj: 25).

The word Ilhad in the verse above refers to every act of disobedience towards Allah. On the authority of Ibn ‘Abbas t, the Prophet ﷺ said: “The most disliked person in the sight of Allah are three” and he mentioned among them “A Mulhid (evildoer) in the sacred precincts.” [ Source: Bukhari.]

2-Prohibition of killing or blood-spilling therein.
Allah the Most High said: “And when we made the House (the Ka’bah at Makkah) a place of resort for mankind and place for safety.” (al-Baqarah: 125).

Whosoever enters Makkah will find safety therein; that is why the Prophet ﷺ said: “It is not permissible for any of you to carry a weapon while in Makkah” [ Source: Muslim.]

The Prophet ﷺ also said: “It was Allah who made Makkah a sacred precinct, and not the people; it is not permissible for whoever believes in Allah and the day of resurrection to spill blood in it and to fell[ Ya’did : to fell.] a tree in it.” [ Source : Bukhari.]
3-Prohibition of the disbelievers and polytheists from entering the sacred precinct (Haram).
Allah, the Most High, said: “O you who believe! Verily, the polytheists are impure. So let them not come near al-Masjid-al-Haram (at Makkah) after this year.” (At-Taubah:28).

And the Prophet had already ordered, while in Mina, for an announcement to be made that: “After this year, no polytheist should come for pilgrimage nor should anybody perform circumambulation of the Ka’bah naked.” [ Source : Bukhari.]

4-Prohibition of hunting, cutting of trees and picking up lost objects while in the sacred precinct.
On the authority of Ibn ‘Abbas t, the Prophet ﷺ said: “Allah made Makkah a sacred precinct, for it was never permitted for anyone before me and neither is it going to be permitted for anyone after me. It has only been permitted for me for an hour of a day. None of its green plants are to be cut[ Yukhtala khalaha: to cut its viable plant.], nor its trees be felled[ Ya’did: to fell], nor its game be startled and no lost object[ Al-Laqtah: a lost object which is found, but whose owner is unknown.] is to be picked up by someone, except who wishes to notify the public (of the lost and found object).” [ Source: Bukhari]
source: islamkingdom