Is an employee sinful if he does not inform his employer of his marriage to avoid a deduction from his salary, knowing that he does not need the housing allocated for married individuals and will remain in bachelor housing?

You are not required to submit the marriage contract to the company if the prohibition of accommodation in bachelors' housing and the salary deduction apply to married individuals who need family housing, as you are considered single. However, if the prohibition applies to all married individuals, you must inform the company of your marriage because Muslims are bound by their conditions.