You should be able to download a high-quality PDF for by searching "Ave Maria de Lourdes PDF" or using the Cantorion or Hymnary websites. If you are a beginner pianist, look specifically for an arrangement in C Major to make the reading easier.
If you are learning this piece, here are a few helpful pointers regarding the musical notation: ave maria de lourdes partition
Originally written with just eight verses, the hymn was so successful that Gaignet eventually expanded it to 120 verses (and sometimes 68) to accommodate the long processions of pilgrims. Musical Structure and "Partition" (Sheet Music) You should be able to download a high-quality