France's PV Atlas

Best estimate: 13,369 MWp, with a 90% range of 11,478–17,762 MWp. That range covers two specific, measured sources of uncertainty -- but not everything that could move this number. Below: what's inside the range, what isn't, how many ground-truth areas it rests on, and how it compares to unrelated data sources.

What's inside the range:

• The two "panel area to power" conversion numbers. One converts rooftop panel area to kWp, the other converts open-ground solar-farm land to kWp. Both are measured against real, confirmed power plants rather than assumed, but each carries its own uncertainty.
• How well the detection model finds panels of different sizes. Its measured precision and recall were checked installation-size by installation-size, and that check itself has a margin of error.

What's outside the range -- and can't be added back in with more arithmetic:

• The ground-truth areas were hand-picked, not randomly sampled, so this isn't a formal statistical margin of error. A figure from purposively chosen areas can be checked, argued with and improved, but it cannot be given a design-based confidence interval the way a random sample of the country's buildings could.
• Ground-truth "complete" means complete as of when that area was mapped, not as of the satellite image used for detection. That cuts both ways, but in the same direction: it makes the model's measured accuracy look slightly worse than it is (recent real installations get scored as false alarms) and its measured miss rate look slightly better than it is (installations built after mapping can't be missed if they were never counted as ground truth to begin with). Both effects point the same way -- this page's figure is more likely an undercount than an overcount.
• This page is a precision floor, not a recall-corrected estimate. France has no glint sample, so the chance that an unmapped detection is real is set to zero and the model's credit collapses to the share of its detections that OpenStreetMap already confirms. The recall correction that roughly doubles comparable Pakistani figures was deliberately not applied: the only French ground truth available to measure it against is a sub-400 m² population, and a correction fitted there would have been manufactured rather than measured.

Treat this as an early-stage estimate from an active research pipeline, not a finished census. What's genuinely new here -- a reproducible way to estimate distributed solar from free satellite imagery and open-source AI, in places where official statistics are sparse or absent -- holds regardless of whether any single number on this page turns out exactly right. Expect these figures to keep moving as the evidence behind them grows.

Fourteen French communes were mapped panel by panel, and what they measured is the limit of the instrument rather than a correction to it. Across 3,335 hand-drawn features on sub-metre imagery, the median installation is 20 m² against a Sentinel-2 pixel of 100 m². Detection recall climbs with array size across those communes (Spearman +0.83) while an independent model reading the same installations from sub-metre imagery is flat, which places the gradient in the sensor and not in the annotator. That is why this page has no small-panel half at all: the per-building classifier that supplies most of Pakistan's estimate scores 0.710 here against 0.857 there, and at a usable precision it flags 16 buildings out of 44,314. The communes are drawn on the map above; they set the floor, they do not raise the total.

France's own register says this page is missing most of the fleet, which is the expected result. The ODRE register puts French PV at roughly 34.6 GWp, several times the figure above, and 92.0% of French installations by count sit below this pipeline's 400 m² detection floor. Per commune, the detection estimators correlate with the register at Spearman 0.45 after retraining in domain, against 0.29 zero-shot -- the retrained model got the geography substantially better while recovering about a third of the capacity. Read the map for where French PV is, not for how much there is.