Employee should not join there immediate client organization

Hello Everyone!! I’m currently working in infosys (JL 4B). Recently there has been an opening in my client organization and my skill set suits the JD very well. But in my infosys offer letter it is mentioned as I should not join my immediate client for 6 months after leaving infosys. Can you please let me know whether this rule is strictly followed in Infosys. If someone violates it, what will be the possible actions taken by Infosys Thanks in Advance!!