A process for the co-production of gasoline and propylene from a heavy hydrocarbon feed with an initial boiling point of more than 340°C using a catalytic cracking unit followed by an oligomerization unit which can function in accordance with two regimes termed "maxi propylene" and "maxi gasoline", in which: • for the "maxi propylene" regime, the feed for the oligomerization unit is constituted by the C4 cut or the C4/C5 olefinic cut derived from catalytic cracking and the effluents from the oligomerization unit are separated into a C8+ oligomer cut which is recycled at least in part to the inlet to the catalytic cracking unit, the gasoline cut from the process being constituted by the gasoline cut produced in the catalytic cracking unit and the oligomer cut derived from the oligomerization unit which is not recycled for catalytic cracking, the catalytic cracking being realized: • -either in a reactor with an ascendant flow, the outlet riser temperature being in the range 510°C to 580°C, preferably in the range 540°C to 590°C, and the C/O being in the range from 8 to 20, • -either in two reactors with ascendant flow, the first FCC reactor working on the heavy feed and running at an outlet riser temperature in the range 510°C to 580°C, preferably in the range 530°C to 560°C and a ratio C/O in the range 5 to 10, and the second FCC reactor achieving the cracking of the oligomers with more than 8 carbon atoms (C8+) coming from the oligomerization unit (feed called "light feed") and running at an outlet riser temperature in the range 550°C to 650°C, preferably in the range 570°C to 620°C, with a C/O ratio in the range 8 to 25, and the oligomerization unit operating at a temperature in the range 100°C to 200°C, preferably in the range 140°C to 160°C at a pressure in the range 0,5 to 10 MPa, • for the "maxi gasoline" regime, the feed for the oligomerization unit is constituted by the olefinic C3/C4 cut derived from catalytic cracking, and the effluents from the oligomerization unit are separated into a C6+ oligomer cut which is added to the gasoline cut derived from catalytic cracking to constitute the gasoline produced by the process; the propylene being obtained in the two regimes from FCC effluents after separation in one or more distillation columns, the catalytic cracking being realized in one or two reactors with an ascendant flow, the outlet temperature being in the range 500°C to 580°C, preferably in the range 520°C to 550°C and with a C/O ratio in the range 5 to 10, and the oligomerization unit operating at a temperature in the range 100°C to 200°C, preferably in the range 140°C to 160°C, at a pressure in the range 2 to 10 MPa, said process being able to run according to the two regimes defined above by switching from one to the other at any time, or according to any intermediate regime. • for the "maxi propylene" regime, the feed for the oligomerization unit is constituted by the C4 cut or the C4/C5 olefinic cut derived from catalytic cracking and the effluents from the oligomerization unit are separated into a C8+ oligomer cut which is recycled at least in part to the inlet to the catalytic cracking unit, the gasoline cut from the process being constituted by the gasoline cut produced in the catalytic cracking unit and the oligomer cut derived from the oligomerization unit which is not recycled for catalytic cracking, the catalytic cracking being realized: • -either in a reactor with an ascendant flow, the outlet riser temperature being in the range 510°C to 580°C, preferably in the range 540°C to 590°C, and the C/O being in the range from 8 to 20, • -either in two reactors with ascendant flow, the first FCC reactor working on the heavy feed and running at an outlet riser temperature in the range 510°C to 580°C, preferably in the range 530°C to 560°C and a ratio C/O in the range 5 to 10, and the second FCC reactor achieving the cracking of the oligomers with more than 8 carbon atoms (C8+) coming from the oligomerization unit (feed called "light feed") and running at an outlet riser temperature in the range 550°C to 650°C, preferably in the range 570°C to 620°C, with a C/O ratio in the range 8 to 25, and the oligomerization unit operating at a temperature in the range 100°C to 200°C, preferably in the range 140°C to 160°C at a pressure in the range 0,5 to 10 MPa, • for the "maxi gasoline" regime, the feed for the oligomerization unit is constituted by the olefinic C3/C4 cut derived from catalytic cracking, and the effluents from the oligomerization unit are separated into a C6+ oligomer cut which is added to the gasoline cut derived from catalytic cracking to constitute the gasoline produced by the process;