An assistance method for assisting an operator in performing a task on a product, the method comprising a step (251, 252) of displaying, superimposed on a view of a scene including a monitored part of the product on which a subtask of the task has to be performed, at least one assistance image (100,..., 136) intended to assist the operator in performing this subtask, said at least one assistance image (100,..., 136) includes at least one highlighting image (100, 102) highlighting the monitored part, wherein the view of the scene is provided by a view source, and the method further comprises the following steps: ∘ tracking a displacement of the view source from a first viewing position in the scene, in which the product occupies a first relative position with a first relative orientation relatively to the view source, toward a second viewing position in which the product occupies a second relative position with a second relative orientation relatively to the view source, ∘ calculating an estimation of the second relative position and of the second relative orientation from the first relative position and orientation and from the tracked displacement, and refreshing the display of the at least one assistance image (100,..., 136) so as to adjust said at least one assistance image (100,..., 136) to the estimation of the second relative position and orientation, characterized in that the first viewing position consists of an initial viewing position in which the first relative position and orientation consist of predetermined relative position and orientation known by a display management unit in charge of displaying the at least one assistance image (100,..., 136), wherein the method further comprises a step of equipping the product with a support comprising a slot able for receiving the view source and adapted so that, when the support is equipped on the product and the view source is received in said slot, the view source is placed in said initial viewing position, followed by a step of placing the view source in the slot of said support. wherein the view of the scene is provided by a view source, and the method further comprises the following steps: ∘ tracking a displacement of the view source from a first viewing position in the scene, in which the product occupies a first relative position with a first relative orientation relatively to the view source, toward a second viewing position in which the product occupies a second relative position with a second relative orientation relatively to the view source, ∘ calculating an estimation of the second relative position and of the second relative orientation from the first relative position and orientation and from the tracked displacement, and ∘ tracking a displacement of the view source from a first viewing position in the scene, in which the product occupies a first relative position with a first relative orientation relatively to the view source, toward a second viewing position in which the product occupies a second relative position with a second relative orientation relatively to the view source, ∘ calculating an estimation of the second relative position and of the second relative orientation from the first relative position and orientation and from the tracked displacement, and refreshing the display of the at least one assistance image (100,..., 136) so as to adjust said at least one assistance image (100,..., 136) to the estimation of the second relative position and orientation, characterized in that the first viewing position consists of an initial viewing position in which the first relative position and orientation consist of predetermined relative position and orientation known by a display management unit in charge of displaying the at least one assistance image (100,..., 136), wherein the method further comprises a step of equipping the product with a support comprising a slot able for receiving the view source and adapted so that, when the support is equipped on the product and the view source is received in said slot, the view source is placed in said initial viewing position, followed by a step of placing the view source in the slot of said support.