They were convicted by Paris court over a scheme to pay her thousands of euros for little work done
Fillon denounces what he calls a dirty tricks campaign and denies having done anything illegal
His poll numbers have suffered and is now in third place behind Emmanuel Macron and Marine Le Pen
Sarkozy piled pressure on the candidate ahead of a crisis meeting
The accusations against Fillon have added to an already unpredictable race
Fillon was due to have a lunch meeting later on Wednesday with Sarkozy
Immigration and security are top issues in the campaign for the presidential elections starting in April.