POST sorting office workers have walked out on strike this week, potentially affecting deliveries in the run-up to Christmas.
Seven trade unions are behind the industrial action, which is in protest at the closure and merger of sorting office sites around France by the end of 2015 and the potential loss of 2,000 jobs.
The one-day strike coincides with the unveiling this morning of La Poste's 2014 budget by its new chief executive, Philippe Wahl. The company denies that the restructuring will lead to redundancies.
Postal deliveries could be delayed by several days as a backlog of mail and parcels builds up.
While Christmas is a busy time for the post office, overall the amount of mail being sent in France is falling by up to 6% every year.
Meanwhile, La Poste has reported a spate of raids on delivery vans.
About 10 attacks have been carried out in the Paris region in recent weeks, with hundreds of Christmas presents going missing as a result.