Below you can see the front view size comparison of Leica X1 and Sony A7 III. Leica X1 is clearly the smaller of the two cameras. Its body is 3mm narrower, 36mm shorter and 42mm thinner than Sony A7 III.
Leica X1 vs Sony A7 III - Front View
Leica X1 vs Sony A7 III - 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