Filling valve group for a filling machine, comprising: - a supply duct susceptible of being placed in fluid communication with a containment tank fixed to a support structure of a filling machine for the flow of a liquid from said containment tank to a container to be filled with said liquid; said supply duct extended along a main extension axis between an inlet section, and an opposite outlet section, at which it is susceptible of being associated with said container to be filled; - an air return tube, which is extended along said main extension axis and is placed at least partially within said supply duct; - a shutter, which is placed to intercept said supply duct and is provided with a narrowing portion fixed to said supply duct and an enlarged portion fixed to said air return tube and movable with respect to said narrowing portion in order to open and close said shutter; - a centering body, mounted on a lower portion of said valve group, placed at the outlet section of said supply duct and comprising a seal placed on a first lower surface thereof susceptible of receiving in abutment the mouth of said container to be filled; said centering body being removably fixed to the lower portion of said valve group by means of first quick coupling means; - a fixed assembly mechanically and rigidly connectable to the support structure of the filling machine, which forms an upper section of the supply duct; - a removable tube, which forms a lower section of the supply duct and is removably fixed to said fixed assembly by means of second quick coupling means, said removable tube carrying, fixed thereto, the narrowing portion of said shutter; wherein the narrowing portion of said shutter fixed to said removable tube comprises a flared wall that is extended from a narrow internal section of said supply duct to said enlarged outlet section of said supply duct for the evacuation of said liquid. - a supply duct susceptible of being placed in fluid communication with a containment tank fixed to a support structure of a filling machine for the flow of a liquid from said containment tank to a container to be filled with said liquid; said supply duct extended along a main extension axis between an inlet section, and an opposite outlet section, at which it is susceptible of being associated with said container to be filled; - an air return tube, which is extended along said main extension axis and is placed at least partially within said supply duct; - a shutter, which is placed to intercept said supply duct and is provided with a narrowing portion fixed to said supply duct and an enlarged portion fixed to said air return tube and movable with respect to said narrowing portion in order to open and close said shutter; - a centering body, mounted on a lower portion of said valve group, placed at the outlet section of said supply duct and comprising a seal placed on a first lower surface thereof susceptible of receiving in abutment the mouth of said container to be filled; said centering body being removably fixed to the lower portion of said valve group by means of first quick coupling means; - a fixed assembly mechanically and rigidly connectable to the support structure of the filling machine, which forms an upper section of the supply duct; - a removable tube, which forms a lower section of the supply duct and is removably fixed to said fixed assembly by means of second quick coupling means, said removable tube carrying, fixed thereto, the narrowing portion of said shutter;