After being acquitted of corruption and fraud charges in 2022, the verdict was appealed and now they are facing trial again in a Swiss court.
"I am hopeful," says Blatter before the first day of the trial.
The case concerns a money transaction in 2011 of two million Swiss francs (nearly 23 million kronor in today's exchange rate) that took place between the then top football officials.
Platini, who was then the chairman of the European Football Association (Uefa), is said to have received the money for consultancy services he performed for the International Football Association (Fifa). The consultancy services were approved by Sepp Blatter, who was then the chairman of Fifa.
The trial is expected to last for four days.