The threat to costs is fading. It is not gone.
For France's construction market, July 2026 brings a reprieve on costs. The line that worried the sector most this spring, energy, is calming down: in the French consumer price index, petroleum products slow markedly (+11.2 % year-on-year in June after +16.6 % in May), and this slowdown has been accelerating since mid-June (source: INSEE, consumer price index, provisional June 2026 estimate). Copper, the backbone of finishing trades and networks, also retreats to around 13,500 dollars per tonne, down on the month (source: London Metal Exchange / Trading Economics, late June 2026). As a result, the pressure on BT and TP cost indices, which had re-accelerated in April and May, should stabilize in the second half. A caveat though: the national construction cost index remains high, around 135 (BT01 index, INSEE), still rising by more than 2 % year-on-year, and June's retreat does not erase three years of cumulative rises. On the volume side, housing authorizations over 12 rolling months are stabilizing, but the most recent SITADEL months remain provisional and understated by the collection lag (source: SITADEL/SDES, Statistical Data and Studies Service of the French Ministry of Ecological Transition, early-2026 data, subject to revision). An isolated very low month there is almost always an incomplete month, not a genuine trough.
🔍 Focus: why copper is the real barometer of your electrical costs
Copper is the invisible metal of construction: cables, switchboards, networks, charging stations, heat pumps. When its price rises, it always ends up in the national electricity cost index for construction (BT47 index) and in the energy and communication networks index (TP12a index), with a 6 to 9-month lag. This mechanism is what pushed those indices above general inflation in 2025 and early 2026. Copper's pullback toward 13,500 dollars per tonne in late June (versus more than 14,500 this spring) is therefore delayed good news: it signals a lull on electrical and network cost lines around the turn of autumn. The lesson for any dry-network or EV charging project (Infrastructures for Recharging Electric Vehicles): tracking copper today means anticipating your costs six months out.
- Copper (LME, London Metal Exchange, the global non-ferrous metals exchange): about $13,500/t in late June 2026, down on the month after a spring peak above $14,500/t (source: London Metal Exchange / Trading Economics).
- Petroleum products (INSEE, CPI): +11.2 % year-on-year in June 2026, after +16.6 % in May. The spring's main cost accelerator is slowing markedly.
- Why the pair matters: copper and energy are the two channels transmitting price shocks into BT and TP indices. Seeing them retreat together is the most reliable signal of a lull in construction costs in the second half.