There are 18 regions, and anyone who got 10% gets to go into the secound round (which happens unless one party reached 50%), but some will withdraw rather than go forward. Also candidates will represent one party but in each region have diverse parties supporting them (except FN, who stand alone)
The overall vote was:
United left: 23%
Green: 7%
Other left: 6%
Total left: 36%
United centre-right: 27%
Other centre-right: 5%
Total centre-right 32%
FN: 28%
Others: 4%
In 2010:
Total left: 50%
Centre-right: 31%
FN: 12%
Others: 7%
For 2015 the lists look like:
Alsace-Champagne-Ardenne-Lorraine
FN 36%
United Right 26%
United Left 16% - will not withdraw
The remainder (22%) of the vote roughly split: 15% left, 7% right, so we can expect:
FN 39%
Right: 32%
Left: 30%
and then if the roughly 1/3 of the left voters vote right, the FN do not win.
Aquitaine-Limousin-Poitou-Charentes
United Left 30%
United Right 27%
FN 23%
Auvergne-Rhone-Alpes
United Right 32%
FN 26%
United Left 24%
Bourgogne-Franche-Comte
FN 31%
United Right 24%
United Left 23%
Balance is roughly 14% left, 8% right, so left should win here, assuming FN gain little support
Brittany
United Left 35%
United Right 23%
FN 18%
Centre-Loire Valley
FN 30%
United Right 26%
United Left 24%
Left should win here
Corsica
Diverse Left 18%
Build Corsica 18%
United Right 13%
Diverse Right 13%
FN 11%
French Guiana
Diverse Right 42%
Diverse Left 30%
Guadeloupe
Diverse Left 44%
United Left 41%
Ile-De-France
United Right 31%
United Left 25%
FN 18%
Languedoc-Roussillon-Midi-Pyrénées
FN 32%
United Left 24%
United Right 19%
Greens 10%
Greens have merged with Left for round 2, so the Left should win
Reunion
United Right 40%
Diverse Left 24%
Democratic Movement 20%
Martinique
Diverse left 39%
Independent Martinique 30%
United Right 14%
Nord-Pas-de-Calais-Picardie
FN 41%
United Right 25%
United Left 18% - has withdrawn
Normandy
United Right 28%
FN 28%
United Left 24%
Pays de la Loire
United Right 33%
United Left 26%
FN 21%
Provence-Alpes-Cote d'Azur
FN 41%
United Right 26%
United Left 17% - has withdrawn
So except for the overseas departements, the FN will have seats everywhere, which is a big advance on 2010, where they only reached round 2 in a few areas.
As for the Presidencies, they are in two horse races in Nord-Pas-de-Calais-Picardie against the centre-right, and the same in Provence-Alpes-Cote d'Azur, and should win against a choice of left and right candidates in Alsace-Champagne-Ardenne-Lorraine.
In 2010 the FN increased their share by only 20% from Round 1 to Round 2 in Nord-Pas-De-Calais, and 22% in Picardie, and just 13% in Provence-Alpes-Cote d'Azur.
So if you were going to place a wager, I'd say that in Nord-Pas-de-Calais-Picardie, the FN will win, what with Calais being the battlefront for immigration, but in Provence they might just be pipped at the post - although even so, the Right need to double their vote there, with tactical voting to keep the FN out.
And the split vote in Alsace should do it for the FN....