A method of installing an assembly for recovering hydrocarbons escaping from an underwater installation, including the following steps: bringing to the destination site a lower or hydrocarbon raising assembly including a rigid canopy having the shape of an inverted funnel and including ballasting compartments, deploying the lower assembly toward the seabed vertically above the underwater installation, assembling at sea an upper or fluid raising assembly adapted to raise the fluid between the seabed and a surface installation, said upper assembly including: ∘ a first flexible pipe adapted to extend substantially vertically between the seabed and the surface, ∘ a collecting chamber connected to the upstream end of the first flexible pipe, ∘ a buoy connected to the downstream end of the first flexible pipe and adapted to be immersed below the surface of the water to maintain the first flexible pipe substantially in its vertical position, ∘ a second flexible pipe extending in the form of a catenary and connected to the downstream end of the first flexible pipe and to the surface installation, towing the upper assembly to the destination site, connecting the collecting chamber to the lower assembly, tensioning the first flexible pipe, connecting the downstream end of the second flexible pipe to the surface installation and the steps 3 and 4 of assembling at sea and towing to the site of the upper assembly and the steps 1 and/or 2 bringing the lower assembly of raising hydrocarbons, and deploying the lower assembly are effected simultaneously. bringing to the destination site a lower or hydrocarbon raising assembly including a rigid canopy having the shape of an inverted funnel and including ballasting compartments, deploying the lower assembly toward the seabed vertically above the underwater installation, assembling at sea an upper or fluid raising assembly adapted to raise the fluid between the seabed and a surface installation, said upper assembly including: ∘ a first flexible pipe adapted to extend substantially vertically between the seabed and the surface, ∘ a collecting chamber connected to the upstream end of the first flexible pipe, ∘ a buoy connected to the downstream end of the first flexible pipe and adapted to be immersed below the surface of the water to maintain the first flexible pipe substantially in its vertical position, ∘ a second flexible pipe extending in the form of a catenary and connected to the downstream end of the first flexible pipe and to the surface installation, ∘ a first flexible pipe adapted to extend substantially vertically between the seabed and the surface, ∘ a collecting chamber connected to the upstream end of the first flexible pipe, ∘ a buoy connected to the downstream end of the first flexible pipe and adapted to be immersed below the surface of the water to maintain the first flexible pipe substantially in its vertical position, ∘ a second flexible pipe extending in the form of a catenary and connected to the downstream end of the first flexible pipe and to the surface installation, towing the upper assembly to the destination site, connecting the collecting chamber to the lower assembly, tensioning the first flexible pipe, connecting the downstream end of the second flexible pipe to the surface installation and the steps 3 and 4 of assembling at sea and towing to the site of the upper assembly and the steps 1 and/or 2 bringing the lower assembly of raising hydrocarbons, and deploying the lower assembly are effected simultaneously.