Leipzig has several towers that look like the logo. The big tower is the new town hall (1905) main tower, the smaller ones may be its two subsidiary towers from an angle not available today; or it may show the tower of the old town hall. Other Brockhaus cards just have the company name printed on the address side, possibly only on cards the firm printed for other publishers. There is an article "The BL Case" on the subject of this logo and attributing it to Brockhaus in The Postcard Album issue 29.