The rules on professional confidentiality incumbent on social security bodies don't allow us to reveal the information about contributors.
You may, however, check that your wages have been declared by consulting your career statement (‘relevé de carrière’). It is available on-line on the pension insurance website; the statement lists the wages declared by your employers each year. The amount of wages pre-printed in the corresponding section of your income tax return is also a proof that your wages have been declared.