Trunk comparison: Citroen C3 vs VW Golf Wagon (Mk5)

Key Differences
The VW Golf 5 offers significantly more cargo length: +13.4 in (25%) when all seats are folded down and +15 in (57%) with the first row upright.
This practically means the Golf can transport longer items and provides a noticeably flatter, longer cargo area when loading with folded seats. For furniture parts, long sports equipment, or longer luggage, the Golf is clearly advantageous.
The Golf's trunk opening is also wider: +5.1 in (15%) at the opening. This makes loading and unloading bulky or wide items easier compared to the C3; wide boxes or furniture can be maneuvered more easily.
The Citroën C3 stands out with a greater depth between the loading edge and trunk floor: +7.1 in (360%). This means the C3 has a significantly deeper trunk floor relative to the loading edge, allowing items to lie deeper in the cargo space.
In practice, this allows volume to be better "hidden" and smaller stacks to remain below the loading edge; at the same time, loading taller items inside the trunk may be limited.
The C3's loading edge is also higher above the ground: +5.5 in (22%). This results in heavier loads requiring more effort to lift in and bulky items needing to be lifted higher. For frequent loading and unloading of heavy goods, the Golf with its lower loading edge is more ergonomic.
Other, Less Relevant Differences
Small deviations under 10% include the greater height of the trunk opening on the C3 (+2 in / 7%) and the slightly larger narrowest width in the Golf (+1.6 in / 4%). These have minor effects on everyday usability and do not significantly change the fundamental advantages or disadvantages.
Conclusion on Usability
If you regularly transport long or wide items (e.g., construction or furniture parts, skis, bulky goods), the VW Golf 5 is the better choice due to its longer cargo area and wider opening.
If, on the other hand, you benefit from a deeper cargo floor—such as to sink luggage or shopping crates deeper or visibly stack them below the loading edge—the Citroën C3 offers advantages, albeit at the cost of a higher loading edge that makes lifting more difficult.