From the photometric data delivered by Gaia mission we are able to select a growing number of microlensing event candidates located mostly in the Galactic Plane. In order to early distinguish genuine microlensing events from other types of outbursts and variables, that are also reported in Gaia Science Alerts system, the spectroscopic follow-up observations are performed for selected transients. We use a wide range of world-class telescopes equipped with low-resolution spectrographs to measure the continuum and detect distinctive absorption and/or emission features in order to classify the targets. Such spectra help us select a sample of microlensing events for which an intensive photometric follow-up monitoring can be conducted. Moreover, for the most interesting targets we apply for high-resolution spectra and study spectral lines in detail to determine physical parameters of the source star in the microlensing event. Finally, the line-of-sight extinction and the distance to the source is obtained as well, therefore, the spectroscopic analysis is essential in constraining the microlensing model and the lens parameters. I will present the status of the spectroscopic study of candidates for microlensing events alerted by Gaia with recent examples of interesting results. Such small-scale operations provide a good training ahead of the forthcoming influx of Galactic Plane transients from the LSST/VRO.