After ninety minutes of trading, the CAC 40, which gained 3.73% last week in its best weekly performance in nearly a year, is down 0.99% at 8,177.69 points. Other indices are also in the red, with London's FTSE 100 losing 0.43% and Frankfurt's DAX 40 shedding 0.97%.

Markets are, however, limiting their retreat, likely because it was improbable that the U.S. and Iran would find common ground over a single weekend, given that diplomatic ties have been severed since the early 1980s, despite occasional exchanges.

Early this morning, Donald Trump indicated that the United States would block vessels entering or leaving Iranian ports starting today at 4:00 p.m. European time. Previously, the U.S. President recalled that "Iran had promised to open the Strait of Hormuz, and they knowingly failed to meet that commitment. This has caused anxiety, disruption, and suffering for many people and many countries around the world. They claim to have laid mines in the water, even as their entire navy, and most of their minelayers, have been completely destroyed."

As for oil prices, they are currently easing after having crossed back above 100 dollars per barrel. In New York, WTI is down 0.98% at 103.60 dollars, while North Sea Brent is retreating 0.89% to 102.14 dollars.

According to Christopher Dembik, Investment Strategy Advisor at Pictet Asset Management: "The market has priced in an additional risk premium following the failure of negotiations between the Americans and the Iranians. The good news, however, is that there is no panic for the moment. Investors are looking at the glass as half-full rather than half-empty. Several alternative routes are now fully operational for transporting oil, notably the UAE's Abu Dhabi-Fujairah pipeline (1.5 to 1.8 million barrels per day) and Saudi Arabia's East-West pipeline (7 million barrels per day). This is obviously not enough to offset the fallout from a blockage of the Strait of Hormuz, but it helps to somewhat soothe fears regarding a lasting oil supply shock."

Today's gainers and losers...

Oil stocks are logically benefiting from such crude price levels, with TotalEnergies rising 1.34% and Viridien gaining 3.24%. Elsewhere in Europe, Italy's Eni is up 1.06% and Norway's Var Energi is advancing 4.05%, further supported by the announcement of an increase in production.

Conversely, companies with high oil consumption are being shunned, such as Air France-KLM, which is stumbling by 4.19%.

Still on the corporate front, Riber continues its surge, soaring 23.56% after already jumping 63.64% over the last four sessions. Last week, the semiconductor industry equipment supplier unveiled improved 2025 results, notably with a gross margin that rose from 14.8% to 15.6%.

Within the CAC 40, the steepest decline belongs to Kering, which is losing 3.36%, penalized by a downgrade from Morgan Stanley, which moved from Overweight to Equal-weight while lowering its price target from 330 to 320 euros.

In Switzerland, Polypeptide Group AG is soaring 12.32%; according to Bloomberg, several private equity firms are reportedly eyeing the company.

On the currency market, the euro is gaining ground against the greenback (+0.15%) and is trading at 1.1692 dollars.

Regarding macroeconomics, investors will have to make do today with U.S. existing home sales for March, to be published at 4:00 p.m.

The quarterly earnings season will kick off in France with the publication, after the European close, of the accounts of luxury giant LVMH.