Child aged six killed by falling branch as hailstorms sweep west of country including parts of the Bordeaux wine region.
French weather agency warns that strengthening storms late Monday coinciding with high tides presents risk of flooding in some areas.
Repairs and cleaning operations began Monday after weekend storms across a swathe of S. France damaged roads, flooded streets and swept cars away.
Many coastal towns built temporary sea barriers as unusually high tides, due to last a month, began on Friday, whipped up by storm-force winds.
The man and woman died, and two other people were seriously injured, in separate incidents in southern France caused by violent storms.
Major congestion was predicted as holiday departures reached a peak at the weekend, while much of the country was hit by violent storms.
A second weather alert in 24 hours was issued Monday for a large swathe of France after rain and hail storms caused havoc overnight Sunday.
The 21,341 recorded bird deaths were mostly Atlantic puffins, guillemots and razor-billed auks which starved after winds blew them off course.
After enduring weeks of storms and flooding, France's western seabord faces a fresh battering from strong winds, heavy rainfall and high tides.
Some 2,000 homes in Brittany were hit by power cuts from fresh storms on Friday, while 7,500 others remained cut off by damage from Storm Dirk.
After winds of up to130 k.p.h. caused havoc in western France, efforts were launched to try to fix damage to electricity network for Christmas.
Bordeaux and Burgundy producers face financial disaster after storms devastated thousands of hectares of vine uninsured because of high costs.
Severe hail storms destroyed thousands of hectares of vine in the region around Bordeaux, leaving uninsured producers facing huge losses.