Below you can see the front view size comparison of Nikon 1 V3 and Panasonic GM5. Panasonic GM5 is 12mm narrower and 5mm shorter than Nikon 1 V3 but it is also 3mm thicker.
Nikon 1 V3 vs Panasonic GM5 - Front View
Nikon 1 V3 vs Panasonic GM5 - Top View
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.
Camera Size Comparison
Select Two Cameras for Size Comparison