I am using sfml-tmxloader to load the .tmx maps from tiled and when I call
sf::Vector2f size = window->getView().getSize();
ml->UpdateQuadTree(sf::FloatRect(0.0f, 0.0f, size.x, size.y));
//get a vector of MapObjects contained in the quads intersected by query area
sf::Vector2f mousePos = window->mapPixelToCoords(sf::Mouse::getPosition(*window));
//NOTE quad tree MUST be updated before attempting to query it
std::vector<tmx::MapObject*> objects = ml->QueryQuadTree(sf::FloatRect(mousePos.x - 10.f, mousePos.y - 10.f, 20.f, 20.f));