From: Rabbi Moshe Sofer
To: Unknown recipient
Jews sold houses on their street to non-Jews and asked whether the Rema's leniency—that a non-Jew occupying a Jewish-owned rental does not invalidate the eruv—extends to an outright sale. The Chasam Sofer rules stringently, arguing that a sale differs from lending or renting because the seller cannot unilaterally negate the eruv prohibition when full ownership transfers to the buyer.
Source: Shu"t Chasam Sofer OC §92