Shares in Eurotunnel which operates the under-sea tunnel between France and England fell by 4.47 percent on Thursday after the European Commission pressed for a cut in prices charged to run trains on the route.
On Thursday, the EU Commission told France and Britain to take action to bring down the charges paid for trains to run through the tunnel.
The Commission held that the prices charged were too high and restricted the development of rail traffic and particularly the movement of rail freight.
The price of shares in Eurotunnel, a private company, fell by 4.47 percent to 5.98 euros. The overall French stock market was showing a fall of 1.85 percent on the CAC 40 index.
At RBC Capital Markets, analysts commented that the effect of the decision by the Commission was "negative" and amounted to "a high threat to profits" if it took effect.