NOVELTY - The structure has two rails (20) extending along longitudinal direction of a horizontal plane. A filling device (160) is installed between the rails, each comprising a base (21) fixed with a roof frame (3). One of the rails includes a fastening unit i.e. lateral rib (75), that extends along vertical direction (Z), opposite to a lower surface (22) of the base. The fastening unit is arranged remotely along transverse direction (Y) from a maintenance part (40). A flange (165) is fixed on the rail and supported at an edge (162) of the filling device, opposite to the fastening unit.    USE - Structure for assembling a solar energy recovery panel i.e. photovoltaic panel, utilized for generating electric energy from sunlight, of a solar energy recovery system (claimed) on a frame i.e. roof frame, of a building. Can also be used for assembling the solar energy recovery panel on other frame such as inclined or non-inclined frame, installed a facade of the building, and a floor.    ADVANTAGE - The flange is fixed on the rail and supported on the edge of the filling device, opposite to the fastening unit, thus simplifying assembling of a panel assembling structure. The fastening unit improves the fixation of the filling device with respect to the rail in a precise manner so as to allow the filling device to satisfy the requirements of shock resistance test i.e. 1200 joules test, by retaining 50 kg mass released from height of 2.4 m for stimulating the fall of a body, and by avoiding the need for piercing the filling device.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a solar energy recovery system.    DESCRIPTION OF DRAWING(S) - The drawing shows a partial sectional view of an edge of a filling device fixed with a rail between a rail fastening unit and a flange.    Transverse direction (Y)    Vertical direction (Z)    Roof frame (3)    Rails (20)    Base (21)    Lower surface of base (22)    Maintenance part (40)    Lateral rib (75)    Filling device (160)    Edge of filling device (162)    Flange (165)