What an interesting postcard!
The photo was made in February 1912 in Luxembourg. It shows Marie-Adélaïde, Grand Duchess of Luxembourg (1894-1924) with her mother Marie Anne (1861-1942). It is a sad way for the women: It is the funeral of father and husband Grand Duke William IV (1852-1912).
They are just in front of The Royal Bio Co. This cinema opened in a hall of the Hôtel de Luxembourg in 1907, and was managed by the owner of the hotel Nicolas Medinger and his son Félix. They later named it in Medingers Kinematograph. It had 350 places and closed in 1912.
Félix Medinger also made little movies of Luxembourg and showed them in his cinema. Above them there is also a movie about the statutory power of the new Grand Duchess on June 18, 1912. He showed this movie at The Royal Bio Co. already on June 22, 1912. The Grand Duchess Marie-Adélaïde went to this cinema with her mother and her five sisters to see this movie on June 25, 1912.
Félix Medinger was a clever business man. I am sure the photo in front of the cinema was his idea. Even there is written the name of the photographer at the left corner: P.C.Schowen (or something like that).
There is a really interesting book about the history of cinemas in Luxembourg: D'Stater Kinoen. Eine Kinogeschichte der Stadt Luxemburg by Paul Lesch. Reading this book is like a journey to this city.