810. Lending a Loaf Before Pesach
114:11 It is permitted for one Jew to lend another a loaf of bread before Pesach on the basis that the borrower will repay it with a different loaf after Pesach. (Even if the borrower violates the law and retains the loaf over Pesach, he must repay the loan. We do not consider this wages for chometz over Pesach, which would be prohibited - Mishnah Brurah 450:1.) Some communities do not permit this.
114:12 If a Jew's chometz is in the domain of a non-Jew, or a non-Jew's chometz is in the domain of a Jew, one should ask a Torah scholar what he should do. This is because there are many details and opinions when it comes to this scenario.