Hollande, Sarkozy said, risks plunging France into a debt crisis, The New York Times reported.
Hollande acts "as if the world did not exist, Europe did not exist, the crisis did not exist," Sarkozy said at a news conference Thursday.
"The situation today that our Spanish friends are going through, that our Greek friends have gone through, reminds us of reality. Look at the situation in Spain, after seven years of Socialist [Party] rule."
Hollande has said he would freeze fuel prices for three months, cut ministers' salaries 30 percent, raise taxes on the most affluent, increase welfare and hire more teachers and police officers. He said he'd also increase welfare payments and guarantee interest rates above the rate of inflation on tax-free savings accounts.
Hollande pledges to balance the budget by the end of a five-year mandate to do so and says he would raise $37.9 billion in new revenue while increasing spending $26.1 billion.
"We are ready to act, ready to make decisions, ready to make changes," Hollande said at a rally in Rennes Wednesday.
Aides to Hollande note Greece had lied about its deficit for years and Spain's financial woes stemmed from a housing bubble and private credit woes, not government spending.