Long version ; International audience ; With the emergence of XML as a new standard for representing business data, new decision-support applications (namely, XML data warehouses) are being developed. To ensure their feasibility, the issue of performance must be addressed. Performance in general, and the efficiency of performance optimization techniques in particular, is usually assessed with the help of benchmarks. However, there are, to the best of our knowledge, no XML decision-support benchmark. In this paper, we present the XML Warehouse Benchmark (XWB), which aims at filling this gap. XWB is based on an original reference model for XML data warehouses, and proposes a test XML data warehouse and its associated XQuery decision-support workload that are derived from the well-known, relational decision-support benchmark TPC-H. Though at an early stage of development, XWB has been successfully used to test the efficiency of indexing and view materialization techniques in XML data warehouses.