The influence of indium surface segregation, As-P exchange at the interfaces and residual incorporation of As and P on the photoluminescence properties of GaAs/GaInP quantum wells, is investigated both theoretically and experimentally. It is shown that these effects may lead to an important energy shift or compensate each other depending on growth conditions. As a consequence the exploitation of photoluminescence spectra in such heterostructures have to be carefully carried out. Four samples have been especially designed to study, in addition to indium segregation, the As-P exchange at the GaAs on GaInP interface. Their low temperature photoluminescence study illustrates the complex behaviours observed in this material system. Photoluminescence spectra are shown to be very sensitive to the interface chemistry, in particular As-P exchange.