Below you can see the front view size comparison of Panasonic FZ300 and Canon M5. Canon M5 is clearly the smaller of the two cameras. Its body is 16mm narrower, 3mm shorter and 56mm thinner than Panasonic FZ300.
Panasonic FZ300 vs Canon M5 - Front View
Panasonic FZ300 vs Canon M5 - 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