The Leeds-based retail logistics company said this will be its first Boomerang returns management service contract in mainland Europe.
Boomerang works with retailers such as online fashion retailer ASOS to provide a bespoke, cost-effective returns service.
Clipper said the new contract represents a major advance for its European operations, which are based in Germany.
S.Oliver is a family-owned fashion company in Bavaria and operates stores throughout Austria, Croatia, Switzerland and the Netherlands as well as Germany.
The Boomerang returns management service will be delivered from Clipper’s existing solutions centres in Munchberg and Hof.
In the UK between 25 and 40 per cent of all clothing and footwear purchases are returned.