The drivers now arrive at the corner slightly earlier as the section of track which links the Tabac left-hander to the start of the Swimming Pool complex has been moved closer to the harbour by 2.5 metres.
A crash at Tabac in 2013 involving Pastor Maldonado and Max Chilton forced the race to be stopped after the TecPro barrier on the outside of the corner became dislodged, blocking the circuit.
The change has shortened the official lap length by three metres to 3.337 kilometres. The race distance of 78 laps will not be altered, Monaco being the only race run for 260 kilometres instead of the usual 305.
The barrier on the inside of turn 15, the right-hander in the Swimming Pool complex, has also been moved since last year to give drivers a better view of the corner.
More than half of the track has been resurfaced since last year, including the start/finish area, Casino, the entry to the tunnel, the Swimming Pool complex and pit lane.