A method for analyzing and selecting a specific droplet among a plurality of droplets, comprising the following steps: - providing a plurality of droplets, - for a droplet among the plurality of droplets, measuring at least two optical signals, each optical signal being representative of a light intensity spatial distribution in the droplet for an associated wavelength channel, - calculating a plurality of parameters from the at least two optical signals, - determining a sorting class for a droplet according to at least two of the calculated parameters, - sorting said droplet according to its sorting class, wherein the plurality of parameters comprises the coordinates of a maximum for each optical signal and a co-localization parameter (Δ) and the at least two calculated parameters used for the determining step comprises the co-localization parameter (Δ); wherein the co-localization parameter is calculated as the distance between the position corresponding to the maximum intensity of a first optical signal among the at least two optical signals and the position corresponding to the maximum intensity of a second optical signal among the at least two optical signals; wherein the plurality of droplets are circulating in a channel; and wherein at least a droplet of the plurality of droplets comprises a first element and a second element (26, 28) chosen in the group of elements consisting of a cell, a fluorescently labelled protein, a cell labelling reagent, a fluorescently labeled antigen, a fluorescently labelled antibody, a particle coated with a biological entity, a nucleic acid, a peptide and a chemical drug. - providing a plurality of droplets, - for a droplet among the plurality of droplets, measuring at least two optical signals, each optical signal being representative of a light intensity spatial distribution in the droplet for an associated wavelength channel, - calculating a plurality of parameters from the at least two optical signals, - determining a sorting class for a droplet according to at least two of the calculated parameters, - sorting said droplet according to its sorting class, wherein the plurality of parameters comprises the coordinates of a maximum for each optical signal and a co-localization parameter (Δ) and the at least two calculated parameters used for the determining step comprises the co-localization parameter (Δ); wherein the co-localization parameter is calculated as the distance between the position corresponding to the maximum intensity of a first optical signal among the at least two optical signals and the position corresponding to the maximum intensity of a second optical signal among the at least two optical signals; wherein the plurality of droplets are circulating in a channel; and wherein at least a droplet of the plurality of droplets comprises a first element and a second element (26, 28) chosen in the group of elements consisting of a cell, a fluorescently labelled protein, a cell labelling reagent, a fluorescently labeled antigen, a fluorescently labelled antibody, a particle coated with a biological entity, a nucleic acid, a peptide and a chemical drug. wherein the plurality of parameters comprises the coordinates of a maximum for each optical signal and a co-localization parameter (Δ) and the at least two calculated parameters used for the determining step comprises the co-localization parameter (Δ); wherein the co-localization parameter is calculated as the distance between the position corresponding to the maximum intensity of a first optical signal among the at least two optical signals and the position corresponding to the maximum intensity of a second optical signal among the at least two optical signals; wherein the plurality of droplets are circulating in a channel; and wherein at least a droplet of the plurality of droplets comprises a first element and a second element (26, 28) chosen in the group of elements consisting of a cell, a fluorescently labelled protein, a cell labelling reagent, a fluorescently labeled antigen, a fluorescently labelled antibody, a particle coated with a biological entity, a nucleic acid, a peptide and a chemical drug.