Django[0] is a popular choice nowadays. There's also DjangoCMS[1] which is "easier" to use for less technical people. And don't forget to examine as many as ecommerce[2] modules as you want.
[0] http://www.djangoproject.com/ [1] http://www.django-cms.org/ [2] https://www.djangopackages.com/grids/g/ecommerce/
