The European Union isn't looking to make an example of the United Kingdom for its decision to leave the EU – it is just a "very difficult" situation, former European Central Bank President Jean-Claude Trichet told CNBC on Monday.
On Monday, Prime Minister Theresa May said she expected any deal with the EU to be struck close to the end of the two-year negotiating period. Only then would Britain know the costs or benefits, she said.
Trichet said it was explained very clearly by those in the "remain camp" that leaving the EU would be "catastrophic" for the U.K.
"I don't think there is any … will to punish Britain. It's only taking the consequence of the fact that the UK that entered in Europe in order to be part of the single market has decided to get out of the single market. That's a simple as that and, of course, the consequences are very bad," he said in an interview with "Closing Bell."
He also doesn't think the future of the European Union will be called into question.
"I'm very, very convinced that resilience of the European project is much, much stronger than is very often analyzed or forecasted," he said.
Meanwhile, in Spain a separatist movement has caused instability. Catalonia's leader said the region will declare independence from Spain "in a matter of days." However, Luis de Guindos, the Spanish economy minister, told CNBC on Monday, "It's very clear the independence of Catalonia is not going to take place."
Trichet is convinced the separatist movement in Spain will fail, but called it a "very difficult challenge."
"It is so clearly in the interest of the Catalonian economy as well as the economy of Spain for the province to remain united with Spain," he said.
As for who should head up the Federal Reserve after Chair Janet Yellen's term expires in February 2018, Trichet pointed to "one good candidate" – Yellen.
"She did a good job, it seems to me," he said.
—CNBC's Silvia Amaro and Reuters contributed to this report.