The official, who spoke on condition of anonymity, was commenting on a government programme for public finances in the coming years, which the Finance Ministry sent to the European Commission last week.
In the document, the ministry stuck by the government's forecast for the public deficit to fall within the EU limit of 3 percent of gross domestic product (GDP) next year for the first time in four years.
The downside risks facing the French economy have increased in recent months, the ministry added, but it stuck to its forecasts for growth of around 2.5 percent this year and next.
Eager to stimulate growth, Finance Minister Herve Gaymard vowed earlier this month to pursue tax cuts for households and businesses in 2006, renewing a tax-cutting programme the government has stalled to reduce the public deficit.
After falling below 3 percent of GDP in 2005, France's deficit would continue to fall to reach 0.9 percent of GDP in 2008, the ministry said in the document, which it published on its Web site (www.minefi.gouv.fr).
The Commission, which supervises EU countries' budgets, halted budget disciplinary action against France and Germany this month, accepting their promises they would run deficits below the EU cap for the first time in four years in 2005.
French economic growth would average 2.5 percent annually over the 2006-2008 period, the ministry said.
Noting that the 2005 budget was based on a euro exchange rate of $1.22, it added, with reference to the economic outlook for France: "The downside risks have however intensified since the draft budget was presented".
Former Finance Minister Nicolas Sarkozy unveiled the budget in September.
"As the exchange rate fluctuations of recent weeks show, the American economy's persistent imbalances continue to keep present the risk of an abrupt weakening of the dollar", the ministry said in the document.
Such a sharp fall in the US currency would slow growth in Europe in the short term, it added. The euro traded around $1.3630 on Friday, just below this week's record high.
Gaymard said earlier this month that the dollar's exchange rate was the "number one risk" to French growth.
The world risked economic catastrophe unless the United States worked with Europe and Asia on currency movements at a February meeting of the Group of Seven rich countries, he said.