  We present the first results obtained in the elaboration of a complete model
of a microquasar where the donor star is from Population III. These stars do
not produce stellar winds so we consider that the mass loss is due exclusively
to matter overflowing the Roche lobe towards the compact object, a maximally
rotating black hole. The rate of accretion is extremely super-Eddington, with
an intense mass loss from the system in the form of winds and jets. We
calculate the relativistic particle content of the jet and the corresponding
spectral energy distribution (SED) considering a lepto-hadronic model.
Prospects for the cosmological implications of these objects are briefly
discussed.
