Passenger numbers on the high-speed rail link fell to 2.6 million in July-September this year, because of the "psychological consequences" of the Nice Bastille Day attack in which 86 people died and more than 400 were injured, according to Eurotunnel chief executive Jacques Gounon.
The French tourism industry was already hit by 2015's two major Paris attacks and Eurostar passenger numbers were down five percent for the first nine months of 2016.
The fall in the number of Eurostar trains in the third quarter led to an 11.7-percent drop in toll fees for Eurotunnel to 74.1 million euros.
But the number of vehicles travelling on shuttle trains hit a new record in July at 317,424.
Following the slide in the pound since Britain voted to leave the European Union Eurotunnel lowered its operating profit target from 560 million to 535 million euros.
But on Wednesday the company pointed out that the British economist is still forecast to grow and the weak pound is having a significant impact on the service of its debt.
Attempts by migrants to smuggle themselves into Britain has not hit the group, Gounon said.
Migrants sneaking into the tunnel hit the company's results last year but the construction of protective barriers has reduced the number of attempts.
Underwater electricity supply
Eurotunnel announced on Tuesday that it is to sell its British freight arm, GB Railfreight, to an investment fund, EQT Infrastructure II.
Work with Germany's Siemens and the UK's Balfour Beatty has started on a 1,000-megawatt electricity supply link between France and the UK, the group announced.
Traffic stopped for five hours
Traffic through the tunnel restarted at 6.30pm on Tuesday after a five-hour interruption because of a power cut.
Seventeen Paris-London Eurostars were cancelled in the afternoon.