[en] The knowledge of the chemical forms of the uranium in micrometer-size particles recovered inside or around a nuclear facility can tell information about the nuclear processes applied in the facility. For the first time a micro-Raman spectrometer combined with a scanning electron microscope has been used to analyse dust particles containing various uranium oxides. The scanning electron microscope detects the particle containing uranium while the Raman spectra allow the identification of the type of uranium oxide [UO₂ or U₃O₈ or UO₃ or UO₄(H₂O)]. We have demonstrated that the presence of most uranium oxides used in nuclear industry can be detected in micrometer-size dust particles