No, students may not ask for a start date postponement or a lesson postponement  during their course.

Before lessons start(minimum 8 days beforehand, by registered letter with proof of receipt): you’ll receive refund for the lessons, less the sum of 100 € for administrative costs and bank charges. In no other circumstances may lessons be postponed or refunded.
- After lessons have started:

No refunds may be given, except in cases of ""force majeure"" only (a major unforeseeable event, student repatriated for health reasons, with supporting document), for which remaining lessons will be refunded, less the sum of 100 € for administrative costs and bank charges. A week’s lessons may not be refunded if the student has attended one of the lessons.

Cancellation requested following the refusal of renewal of the residence permit: paid courses will be refunded upon presentation of official proof issued by the Prefecture, minus the sum of 100 € administrative and bank fees (subject to receipt of the request 8 days minimum before the beginning of the courses).

Changing level: your teacher needs to have noted that your level is not suited to that of his/her class. You should therefore make your request to your teacher.