The change in policy regarding overtime in France is likely to have an effect on the short-run aggregate supply curve. In the short run, the aggregate supply curve is upward sloping, which means that as the price level increases, firms are willing to produce more output.
The change in policy would likely increase the cost of labor for firms that require their employees to work more than 35 hours per week. This increase in the cost of labor would increase the firms' marginal costs, which could shift the short-run aggregate supply curve upward and to the left. This is because the firms would need to increase their prices to cover the additional labor costs, which would result in a decrease in the quantity of goods and services supplied at any given price level.
However, the magnitude and direction of the shift would depend on various factors, such as the elasticity of labor supply and the extent to which firms can pass on the increased costs to consumers in the form of higher prices. Additionally, the long-term effects of the policy change may differ from its short-term effects.