Inclusion Criteria:  Male or female, aged 18 - 70 years Provision of signed and dated informed consent form Stated willingness to comply with all study procedures and availability for the duration of the study Diagnosed with CRS based on the diagnostic criteria of the EPOS guideline Registered with a social security scheme or covered by such a regime  Exclusion Criteria:  Antibiotics or oral corticosteroids intake in the month prior to the study Endoscopic sinus surgery in the past 6 months Cystic fibrosis Wegener's granulomatosis Immunodeficiency Defective access to middle meatus Lidocaine allergy Known hypersensitivity/allergy to any component of the test device Pregnant/Lactating female or absence of efficient contraception Under tutorship or guardianship