Since January 2025, the introduction of tariff barriers on US imports has destabilised world trade. The various measures taken (universal customs duties of 10%, 30% on Chinese products, 25% on Canadian and Mexican imports, 25% on certain products such as automobiles, and 50% on steel and aluminium) have raised the average effective rate of US customs duties to a historically high level.

For US enterprises and consumers, the customs duties mean a sharp rise in the price of imported products and therefore losses of purchasing power and margins, leading to a reduction in US imports. These measures will therefore first spread to the world’s different economies via the trade channel. In the rest of the world, the introduction of customs tariffs is likely to reduce the output of sectors that export to the United States. In Germany, the automotive industry is set to be the main sector affected; in China, it is expected to be textiles, and in France, it is likely to be the transport-equipment-manufacturing, beverages and food-product sectors. The French departments with the greatest exposure are those specialising in aeronautics (Haute-Garonne, Hautes-Pyrénées, Seine-et-Marne), shipbuilding (Loire-Atlantique) and wines and spirits (champagne in Marne, cognac in Charente).

The impact of the trade shock should initially be limited to the industrial branches, before gradually spreading to the entire production system and extending into the tertiary sector. These comprehensive trade effects can be quantified using an analysis based on an Inter-Country Input-Output Table (ICIO). All in all, via trade channels, Germany and China should be more vulnerable to the increase in US customs duties (by -0.2 and -0.3 points of GDP respectively) than France (-0.1 point). However, the shock is set to hit certain sectors very hard: for the German car industry, the loss of value added is expected to reach 1.3 percentage points. However, these are medium-term effects once all the adjustments have been made.

In addition to the trade channel, the announcements by the new US administration have triggered a wave of reactions affecting the entire global economy, including a sharp decline in oil prices, a drop in world stock market values, tensions on bond markets, depreciation of the dollar against the euro and growing economic uncertainty. In the short term, the uncertainty caused by the US announcements may trigger anticipatory behaviour, such as precautionary imports, generating temporary but volatile effects on trade. A comprehensive international economic model is required to take account of all these phenomena, outside the confines of the trade channel. In the absence of a response from partners, simulations using the Oxford Economics model estimate an effect of around -0.1 GDP point for France and Germany in 2025, and a slightly higher effect for China (-0.2 points). The effect in 2026 is expected to be greater for Germany and China (-0.7 points) than for France (-0.4 points). The implementation of countermeasures by the United States' partner economies is likely to exacerbate the shock for all the world's economies. However, these estimates do not take account of potential non-tariff measures, such as quantitative restrictions on inputs (such as rare-earth metals in China)...