We were delighted to discover in the October 2014 issue of MAGNIFICAT magazine, the art essay on St. Margaret Mary! If you have not read it, you can access it here:

https://www.magnificat.net/english/flip_com_oeuvre/index.html

In addition to a good review of the development of the Sacred Heart devotion in general and St. Margaret Mary’s place in it, there is mention of the Sacred Heart’s influence on French history. The copy of the painting may be a source of meditation for you.