Effects of Atalante Exoskeleton on Gait Recovery in Non- or Poorly Ambulatory Patients With Hemiparesis in the Acute/Subacute Phase (Month 1 to 4)

Inclusion Criteria: * \>18 years old * First clinically significant disability due to stroke * Hemiparesis in acute-subacute phase (1 to 4 months since lesion) due to a stroke * Functional Ambulation Category score (FAC) \<2 * Patient with health insurance * Informed and willing to sign an informed consent form approved by the Ethics Committee. For clarity, if a motor impairment prevents the subject from signing by himself, he/she can still be included if the signature can be done by an impartial witness. Exclusion Criteria: * Muscle overactivity in hip adductors, hamstrings, quadriceps and plantar flexors, which interferes with exoskeleton use, based on clinician investigator's opinion * Recent fracture (\< 3 months) or any therapy inducing secondary osteoporosis * Excessive joint mechanical pain in the lower limbs based on clinician investigator's opinion * Pressure sore grade I or more over contact zones with Atalante system, according to the International Pressure Ulcer Classification System NPUAP - EPUA * Medical contra-indication to medium intensity physical strain * Orthostatic hypotension (loss of \> 20 mmHg systolic BP after 3 minutes in standing position) * Uncontrolled seizures * Morphological contra-indications to the use of Atalante (as per user's manual) * Pregnant woman * Adults who lack the capacity to provide informed consent, and all those persons deprived of their liberty in prisons or other places of detention * Concurrent participation in another interventional trial