La veine des Irlandais.
lah VENN day zeer-lah-DAY.
The luck of the Irish.
Which, you will find if you look it up, may be either bad or good. Potato famine or pot of gold? Colonial conquerors or California silver mines? In any case, the French do not celebrate St. Patrick’s Day as the Americans do. (Nor, for that matter, do the Irish themselves.) In mostly-Catholic Europe, St. Patrick’s Day is just another saint’s feast day, or name day.
Notwithstanding that, here is a bouquet of lucky expressions in French for you:
Bonne chance! Good luck! bun SHAHSS
Quelle veine! What great luck! (colloquial) kell VENN
Quelle déveine! What bad luck! (colloquial) kell day-VENN
A more common way to wish someone luck in French: Bon courage! Good luck (hang in there)! baw koo-RAHZH
Ça porte malheur. That brings bad luck. sah port mah-LUHR.
Il a une veine de pendu. He has the luck of the devil. (Literally: he has the luck of a hanged man.) Not the kind of luck you would want! ee lah ewn VENN duh pah-DEW.
Veinard! Veinarde! You lucky thing! (The first refers to a male, and the second to a female.) vay-NAAR! vay-NAARD!
Mon chiffre porte-bonheur. My lucky number (literally: my number that brings happiness!). maw SHEE-fruh PORT buh-NUHR.