France cleared a €74.53/MWh day-ahead mean on Monday 27 July, then €102.35, €115.70 and €115.61 across the three sessions that followed, reaching €129.93 by mid-morning on Friday 1. France, whose fleet is roughly two-thirds nuclear and largely insulated from the wind swings that move German prices, rose anyway. It rose by €27.58/MWh between 28 and 31 July against Germany's €30.40. France absorbed almost the entire German move.
That leaves Germany dearer by roughly €7 to €17/MWh through the week, an order of magnitude narrower than the €43.09 France held below Germany on Sunday 26 July . The pattern is not new: the same spread compressed to €18 to €26 in early July before reopening.
France and Germany trade into a single day-ahead market coupling arrangement with finite interconnector capacity, so as long as the cable is not congested the two zones converge on whichever plant is marginal across the region. Once German gas turbines are setting that price, French nuclear does not price independently of them; it prices against them, at a discount limited by transfer capacity rather than by its own cost stack. A position long France against Germany on a nuclear-cost thesis therefore shrinks every time the German spark spread turns positive, which is the opposite of how such a spread is usually sold.
