A system for protecting a user traveling on a vehicle provided with a steering handlebar, the vehicle including a frame extending according to a longitudinal direction and having a front portion provided with a pivot, and a steered wheel pivotally mounted on the steering handlebar according to a wheel axis perpendicular to a direction of movement, the steering handlebar being pivotally mounted on the pivot of the frame to modify the direction of movement, the protection system comprising: - a support having a first direction and configured to be mounted on a location of the vehicle selected amongst the front portion of the vehicle and the steering handlebar, the first direction being coincident with the longitudinal direction when the support is mounted on the front portion of the vehicle, and with the direction of movement when the support is mounted on the steering handlebar, - a protection device (25; 25') comprising an inflatable protective structure (26; 26') mounted on the support, the protective structure (26; 26') being configured to form at least one portion of a front protective panel (27; 27') intended to protect the user according to the first direction, wherein the protective structure (26; 26') includes two front posts (28; 28') secured to the support, and the protection device (25; 25') further comprises a front protective net secured to the front posts (28; 28'), the front posts (28; 28') and the front protective net forming the front protective panel (27; 27'), wherein the protection device (25; 25') has: - as long as no accident situation is detected, an inactive state in which the protective structure (26; 26') is deflated, the front protective panel (27; 27') being folded over the support, the front posts (28; 28') and the front protective net being folded over the support, - when an accident situation is detected, an active state in which the protective structure (26; 26') is inflated such that the front protective panel (27; 27') extends from the support perpendicularly to the first direction while having a thickness according to the first direction smaller than a width according to a second direction perpendicular to the first direction, and a height according to a third direction perpendicular to the first and second directions, the protection system being characterised in that the protection device (25; 25') is configured so that in the active state, the front posts (28; 28') extend from the support according to the third direction and at a distance from each other according to the second direction, and at least one portion of the front protective net is stretched between the front posts (28; 28'). - a support having a first direction and configured to be mounted on a location of the vehicle selected amongst the front portion of the vehicle and the steering handlebar, the first direction being coincident with the longitudinal direction when the support is mounted on the front portion of the vehicle, and with the direction of movement when the support is mounted on the steering handlebar, - a protection device (25; 25') comprising an inflatable protective structure (26; 26') mounted on the support, the protective structure (26; 26') being configured to form at least one portion of a front protective panel (27; 27') intended to protect the user according to the first direction, wherein the protective structure (26; 26') includes two front posts (28; 28') secured to the support, and the protection device (25; 25') further comprises a front protective net secured to the front posts (28; 28'), the front posts (28; 28') and the front protective net forming the front protective panel (27; 27'), wherein the protection device (25; 25') has: - as long as no accident situation is detected, an inactive state in which the protective structure (26; 26') is deflated, the front protective panel (27; 27') being folded over the support, the front posts (28; 28') and the front protective net being folded over the support, - when an accident situation is detected, an active state in which the protective structure (26; 26') is inflated such that the front protective panel (27; 27') extends from the support perpendicularly to the first direction while having a thickness according to the first direction smaller than a width according to a second direction perpendicular to the first direction, and a height according to a third direction perpendicular to the first and second directions, - as long as no accident situation is detected, an inactive state in which the protective structure (26; 26') is deflated, the front protective panel (27; 27') being folded over the support, the front posts (28; 28') and the front protective net being folded over the support, - when an accident situation is detected, an active state in which the protective structure (26; 26') is inflated such that the front protective panel (27; 27') extends from the support perpendicularly to the first direction while having a thickness according to the first direction smaller than a width according to a second direction perpendicular to the first direction, and a height according to a third direction perpendicular to the first and second directions, the protection system being characterised in that the protection device (25; 25') is configured so that in the active state, the front posts (28; 28') extend from the support according to the third direction and at a distance from each other according to the second direction, and at least one portion of the front protective net is stretched between the front posts (28; 28').