The Chapel at rue du Bac where Our Lady appeared to Catherine Laboure now has an official web site. <a href-http://www.chapellenotredamedelamedaillemiraculeuse.com
At present it is only available in French at http://www.chapellenotredamedelamedaillemiraculeuse.com/FR/a.asp but there are obviously plans for English, Spanish and Portuguese.
Among the features of the French site are the hours of public access and a 15 step guided tour.
For other chapels of the Miraculous Medal arouind the world visit the links page at http://www.amm.org/