Sure. Here is my request
https://***-***-***.mktorest.com/rest/v1/leads.json?access_token=f1e4dbfc-7f39-4016-a832-57bcffa4daee%3Aab&fields=email&filterValues=Germany&filterType=country
here is the reply
{u'errors': [{u'code': u'1011',
u'message': u"Lookup field 'country' not supported"}],
u'requestId': u'fa19#149aac48b50',
u'success': False}