The French National Institute of Statistics and Economic Studies (INSEE) has published the public debt figure for the third quarter of 2025.
The public debt-to-GDP ratio stood at 117.4%. The graph, which begins in 1815, uses annual data. The 2025 figure is for the third quarter, which has just been published.
The pattern observed in all developed countries is that war has historically been the primary cause of public debt. This is evident in 1870, 1814, and 1940. Cannons were purchased with the expectation of later payment.
Historically, it was relatively rare to see debt increase outside of these specific situations. This was the case in the USA during the Great Depression.
The ratio fell at the end of the conflict because spending decreased, and there was a significant rebound in GDP.

In the 1950s and 60s, exceptionally high growth enabled a dramatic reduction in public debt in France. The second graph shows the different growth regimes in France since the end of the Second World War.
Trend growth has fallen from 5% to 1%. With the same level of debt flow, the debt-to-GDP ratio inevitably deteriorates with a slowdown in growth.

A few remarks

• The ratio in Q3 2025 exceeds that of 2020 during the pandemic. However, the shock has long since subsided. The recent anomaly lies here. Debt increases to mitigate a shock over time, but it should then decrease. This is not happening. The problem lies elsewhere.
• I have drawn a line in red from the low point in 1975 to the present. The public debt-to-GDP ratio can be approximated by a straight line. Consequently, the recent and current period does not appear to be an anomaly.
• The extraordinary growth of the social model has an equilibrium that requires income growth greater than that which can be produced by the economy.
• The social model has adjusted, but always in reaction to reduced growth.
• Public debt is then the most convenient way to balance the accounts.
• The social model would therefore need to be scaled back, hoping to maintain business growth and see the trend reverse. It’s a complex choice and a gamble no one wants to take spontaneously.
• Public debt is a collective choice, and its stabilization is also a collective choice. The German consensus has demonstrated this on numerous occasions, as has Sweden with its structural reforms.
• It is up to the French to collectively understand that their interest lies in being able to continuously adapt to a changing world that does not wait for them.