The crew took off from runway 13 at Montpellier-Frejorgues Airport (MPL) for an IFR flight bound for Albert/Bray, France. with two passengers. During initial climb, the co-pilot, PF, found that the left horizon was unusable. The Captain, in the right seat, took over the controls and used the information from the right horizon to continue the flight. The co-pilot noticed that the amber generator lights were on. He tried unsuccessfully to stop and start them. The captain decided to abort the flight. He asked the co-pilot to extend the landing gear. During the extension sequence, the aircraft suffered a total electrical failure. The lighting conditions in the cockpit were then very dark and the crew had difficulty in reading the instrument displays. The captain asked the co-pilot to shine a flashlight on the instruments. He briefly saw the threshold of runway 31R. The co-pilot suggested that he go around as he was unsure that the gear was locked down. During the aerodrome circuit at low height the co-pilot continued extending the landing gear manually. The emergency landing being imminent, the co-pilot stopped doing this, even though he was unsure that the gear was locked down because he didn’t feel enough resistance to indicate that the gear was extended and locked down. Given the weather and the difficulty of reading the instruments, the captain decided to land. During the landing roll the main landing gear collapsed slowly, the fuselage came into contact with the ground and the aircraft stopped on the runway.