A heat exchanger including a stack of plates spaced apart in such a way as to present an assembly of intermediate spaces allowing a fluid circulation between the plates. The assembly of intermediate spaces including a plurality of intermediate multi-fluid spaces each intended for circulation of a plurality of fluids between two adjacent plates, and each partitioned into a plurality of compartments separated from each other in a sealed manner. Each compartment is configured for the circulation of one fluid from the plurality of fluids, and is in fluid communication with one of the compartments of a distinct intermediate multi-fluid space.