Sepp Blatter turned 80 on Thursday, with a party planned at a luxury hotel in Zurich, as Switzerland's criminal investigation into his FIFA presidency looked set to intensify.

After his four-decade career at world football's governing body formally ended on February 26 with the election of his successor, Gianni Infantino, Blatter was "extremely busy with the preparations for his birthday," his spokesman Klaus Stoelkher told AFP.

But on Wednesday, France announced that it had seized documents in connection with the suspect 2.0mn Swiss franc ($2.0mn) payment he made to Frenchman Michel Platini - a transaction that led to Blatter's ban from football.

The French search followed a request from Switzerland's top prosecutor who is probing Blatter over criminal mismanagement at FIFA and the possibly "disloyal" payment he made to Platini, the suspended president of European football.

Blatter told AFP that he saw no malice in the timing of the search.

"I don't think that the Swiss prosecutor's office considered that it was the day before my birthday," he said, adding that news of the search would not spoil his celebrations.

"I don't see how this could ruin this lovely day."

Roughly 100 people have been invited to the party at the Savoy Baur en Ville hotel in Zurich, which has been organised by Blatter's daughter Corinne, one the ex-FIFA boss's most outspoken defenders throughout the scandal that brought down his presidency.

Aside from friends, the guests include Jean-Paul Brigger, a former Swiss international and long-time Blatter collaborator at FIFA and Rene Fasel, the head of the International Ice Hockey Federation.

A cake - with no candles - and a brief speech by his partner Linda Gabrielian are on the agenda.

Despite Blatter's departure from FIFA in disgrace, some members of the body are expected to attend, including acting secretary general Markus Kattner, who many believe faces a demotion under Infantino.

Blatter worked as a journalist and for the Swiss ice hockey league before joining FIFA in 1975 as the organisation's development director, when it had roughly a dozen employees and worked out of small building in Zurich.

He rose to the post of secretary general under president Joao Havelange, before his election as president in 1998.

FIFA's size and revenues exploded under his administration, but criminal indictments in the US and multiple other allegations claim that graft also flourished.

With the organisation plunged into a devastating scandal, Blatter was provisionally suspended in October.

Last month, a FIFA appeals upheld an earlier verdict that found Blatter guilty of ethics violations in connection with the Platini payment, but reduced his ban from eight years to six.