No matter where your child goes to school, you can find a summary of holiday calendars for schools in Luxembourg.
Luxembourg School Holidays 2009-2010 (in French)
School Holidays in Luxembourg (in French) from 2008 until 2013.
St George's School Calendar 2009-20010
European School System School Calendar 2009-2010 and 2010-2011
2009 Public holidays in Luxembourg
2009 School holiday dates throughout Europe (in French)