Narrated Abu Rafi`:

The Prophet (ﷺ) said, "The neighbor has more right to be taken care of by his neighbor (than anyone else)." Some men said, "If one wants to buy a house for 20,000 Dirhams then there is no harm to play a trick to deprive somebody of preemption by buying it (just on paper) with 20,000 Dirhams but paying to the seller only 9,999 Dirhams in cash and then agree with the seller to pay only one Dinar in cash for the rest of the price (i.e. 10,001 Dirhams). If the preemptor offers 20,000 Dirhams for the house, he can buy it otherwise he has no right to buy it (by this trick he got out of preemption). If the house proves to belong to somebody else other than the seller, the buyer should take back from the seller what he has paid, i.e., 9,999 Dirhams and one Dinar, because if the house proves to belong to somebody else, so the whole bargain (deal) is unlawful. If the buyer finds a defect in the house and it does not belong to somebody other than the seller, the buyer may return it and receive 20,000 Dirhams (instead of 9999 Dirham plus one Dinar) which he actually paid.' Abu `Abdullah said, "So that man allows (some people) the playing of tricks amongst the Muslims (although) the Prophet (ﷺ) said, 'In dealing with Muslims one should not sell them sick (animals) or bad things or stolen things."