Does the employee have the right to refuse to sign...

If the employment contract stipulates a condition of non-competition, then in this case, when the worker performs another job, the employer sees that he is a competitor in the field of his work, and that the worker joining this job may cause him harm as a result of disclosing work secrets. In this case, if the worker has not completed the procedures Joining the new job. In this case, the employer can file a complaint against him with the Ministry of Labor for not issuing him a work permit. However, if he has already joined the job, in this case the employer can file a lawsuit to demand financial compensation from the worker. In both cases, the discretion is with the Ministry of Labor and the court.
In this regard, the law stipulates the following:
Article 127
  If the work assigned to the worker allows him to know the employer’s clients or to know the secrets of his work, the employer may stipulate that the worker, after the end of the contract, not compete with him or participate in any project competing with him. For the validity of this agreement, the worker must be fully twenty-one Gregorian years old at the time. It must be concluded and the agreement must be limited in terms of time, place and type of work to the extent necessary to protect the legitimate business interests.