Try the below procedure, it may work.
LAGUNA RF RE-PROGRAMMING
1. Turn Ignition OFF.
2. Press the central door locking button (the one near the handbrake) for more than 5 seconds. Note:
the door should lock then unlock.
3. When this happens, 15 seconds is allowed and the immobiliser warning
4. Press the working remote control once, the doors should lock and unlock.
5. Press the second remote control once, the doors should lock and
6. Check the remote control unlocks and locks the doors.