That is a slightly restyled Mazda3 hatch with an AWD option. The side swoop is gone, the taillights and the badge under the rear window have been pulled back a few inches to make the tail end a little bit squarer, and there is a chrome strip running between the taillights like the CX-9. On the inside, they're virtually identical. This is what the CX-3 should have been. They should have just called the sedan version the Mazda3, added an AWD option to the hatch and called it the CX-3. They would have owned the subcompact CUV segment.
Here are some cargo volume sizes:
Mazda CX-4: ~400L (AWD)
Mazda3 hatch: 572L
Mazda3 sedan: 351L
Mazda CX-3: 286L with AWD, 351L with FWD