Security and justice, Marine Tondelier
Prisons and sentences: 100% numerus clausus, moratorium on new prison places
Direction of change: decrease, compared with current law.
The lever. Prison places, prison overcrowding, minimum sentences, short sentences, sentence adjustments and alternatives to imprisonment. Direction rule: ↑ more prison places or heavier sentences.
« Limiter la surpopulation à 100 % des capacités dans tous les établissements pénitentiaires (actuellement 133 %) et garantir des conditions dignes de détention face aux traitements inhumains et dégradants encore en place. Adopter un moratoire sur la construction de nouvelles places de prison en dehors de celles destinées à remplacer les prisons insalubres. »1Translation by the editorsLimit overcrowding to 100% of capacity in all prisons (currently 133%) and guarantee dignified conditions of detention in the face of the inhuman and degrading treatment still in place. Adopt a moratorium on building new prison places other than those intended to replace insalubrious prisons.
Encoding
| Parameter | Current law | Programme | Effective date or horizon |
|---|---|---|---|
| Net prison places delivered by 2032 | 0 places | -3,000 places* (outside the range measured by the source: linear extrapolation) (assumption by the editors, see the costing) | full year 2032, €bn/year |
Costing
Announced by the candidate
not announced
The programme does not cost this measure.
Published costings
none
No external costing of this position recorded to date.
Our calculation
+€0.3bn* (outside the range measured by the source: linear extrapolation)
per year for the public accounts, saving, range +€0.2bn to +€0.5bn.
* Outside the range measured by the source: linear extrapolation (measured range: 0 to 15,000 places).
The calculation
- Net prison places delivered by 2032: (-3,000 − 0) ÷ 1,000 = -3 times “1,000 net places delivered by 2032 (annual operation + investment spread over 2027-2032)”, each a cost of €0.11bn (0.08 to 0.15). Proposed value outside the range measured by the source: linear extrapolation (measured range: 0 to 15,000 places). Investment cost measured on the « 15 000 places » plan. Beyond 15,000 places, or for a decrease, linear extrapolation, flagged as such.
Assumption by the editors. Partial costing. Reading adopted: the moratorium halts the places of the « 15 000 » plan on which work has not yet started (4,110 gross places at the study stage or with contracts awarded, Sénat, November 2025), i.e. about 3,000 net places at the ratio observed for the facilities delivered (73%, which removes replacement places), costed at the cost of one place (operation and investment); a decrease outside the measured range, linear extrapolation. Not costed: the occupancy cap at 100%, whose effect (about 21,700 prisoners above the number of places, to be given sentence adjustments) has no published estimate. Overlap with “Additional public investment, per year” examined: one is a cost, the other a gain: with no shares declared for this case, both amounts are added (the higher-amount rule only applies between two costs or two gains).
Coefficient calculated by the editors from AN, rapport spécial PLF 2026, Justice: the position is marked as an assumption by the editors.
Current law, sources and limits of the cost schedule
Current law. At 1 September 2025: 84,311 prisoners for 62,614 operational places, i.e. an occupancy rate of 134.7%. « 15 000 places » plan by 2027, well behind schedule. Modular prisons (target of 3,000 places). Minimum sentences were abolished in 2014.
Horizon. full year 2032, €bn/year
Limits. Investment: €5.55bn / 15,000 ≈ €370k per place, i.e. about €0.06bn per year for 1,000 places if the works are spread over six years. Running costs: about €40k to €60k per place per year, estimated from Title 2 and the operating appropriations of programme 107. This ratio is overestimated because the programme also funds probation (SPIP). Minimum sentences cannot be costed directly: their cost runs through the number of additional prisoners, hence of places. At 134% prison density, additional prisoners without new places cost the budget almost nothing, but worsen overcrowding. Running costs checked against a source: the Cour des comptes (Court of Audit) (2023) gives €105 per day of detention, i.e. about €38m per year for 1,000 prisoners (running costs only, without investment). With investment spread out (about €0.06bn per year for 1,000 places), this gives about €0.10bn for 1,000 places, within the range used. The Council of Europe (SPACE I 2023) gives €127 per day, cited in a National Assembly document. 15,000 plan: 5,411 net places delivered by autumn 2025; the places still to come are published only in gross terms (about 6,500), which prevents costing a moratorium on the remaining places. Rule on public bases (18 October 2026): a moratorium on new places, excluding replacement places, is costed through the parameter as a negative value (extrapolation, flagged as such) on the gross places not yet under construction (2,560 at design-study stage, 1,550 with contracts awarded, i.e. 4,110), converted into net places at the ratio observed for the facilities delivered (5,411 net for 7,384 gross, 73%, which takes out the closures of replaced prisons): about 3,000 net places (editors' calculation; the 2,388 gross places under construction are treated as committed).
- AN, rapport spécial PLF 2026, Justice, 2025-10: « Au 1er septembre 2025, le nombre de détenus était de 84 311 ... pour 62 614 places opérationnelles, ce qui représente une densité carcérale de 134,7 % ; En 2026, les crédits demandés au titre 2 s'élèvent à 3,58 milliards d'euros ... Hors CAS Pensions, ces crédits représentent 2,33 milliards d'euros »
- Sénat, rapport d'information n° 37 (2023-2024), A. Lefèvre, « 15 000 places ... mission impossible ? », 2023-10-18: « au mois de juin 2023, le coût prévisionnel révisé atteignait désormais 5,55 milliards d'euros ... le coût total du plan 15 000 pourrait excéder les 6 milliards d'euros »
- Cour des comptes, « Une surpopulation carcérale persistante, une politique d'exécution des peines en question », rapport public thématique, 2023-10: « « Pour le programme 107, la direction de l'administration pénitentiaire (DAP) calcule un agrégat, le coût d'une journée de détention (JDD) pour le milieu fermé. […] Il ne constitue pas un coût complet et n'intègre pas les dépenses d'investissement. […] En moyenne une journée d'incarcération en établissement pénitentiaire coûte 105 € par détenu. » »
- Sénat, rapport général n° 139 (2025-2026), tome III, annexe 17 « Justice » (A. Lefèvre), 2025-11-24: « « Au moment de la présentation du présent projet de loi de finances, 24 établissements du plan 15 000 avaient été livrés, soit 7 384 places brutes créées et 5 411 places nettes, compte tenu de certaines fermetures d'établissements. » ; « 2 388 places brutes sont en travaux, 2 560 places brutes sont en phase d'études de conception et 1 550 places brutes sont concernées par des marchés attribués. » »
How to read these amounts. These are static costs and revenues, with no feedback effect, over a full year: nothing on growth, employment or the revenue that economic activity would gain or lose. A higher net cost does not on its own make a worse policy, nor net savings a better one: each programme rests on an economic model (demand-led stimulus, lower compulsory levies, consolidation of the public accounts…) that the cost schedule does not settle. GDP itself measures a volume of activity, not well-being or the usefulness of what is produced. Economic models and feedback effects.
- Pour une prospérité écologique, programme des Écologistes, p. 170. Open the document at this page.
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