@MaximeDemers , if you're wanting a script, trying the following, which you can set up as a script with 3 parameters:
import arcpy
inFC = arcpy.GetParameterAsText(0)
tolerance = arcpy.GetParameterAsText(1)
outJSON = arcpy.GetParameterAsText(2)
arcpy.management.CopyFeatures(inFC, r"memory\outFC")
arcpy.edit.Generalize(r"memory\outFC", tolerance)
arcpy.FeaturesToJSON_conversion(r"memory\outFC", outJSON)
David
..Maps with no limits..