Thanks to Martin for this!
https://brandenburg.museum-digital.de/index.php?t=objekt&oges=7488
Google translate for that page:
The statue of Apollo by François Sigisbert Adam (1710-1761) depicts the adolescent god turning to the statue of Venus Urania, which is the equivalent in the marble hall of the Sanssouci Palace. He is holding a tablet with the words "Te Sociam Studeo Scribundi's Versibus Esse, Quos Ego De Rerum Natura Pangere Conor." ("Help me if I try to put nature in verse"). The verse is taken from the Venus hymn of the Roman poet and philosopher Lucretius (between 99 and 94-55 or 53 BC), which marks the beginning of his writing "De rerum natura", which is dedicated to Epicurean natural philosophy. In the Venus hymn he sings of love as the motor of all being. The constellation of both sculptures in the Marble Hall links the process of knowledge with the concept of love and beauty. All in all, Lucretius's writing is committed to "the knowledge of the truth" and "the work of nature". Frederick II had this text in his library several times in Latin-French editions. Both statues in the Marble Hall were created in the first two years of the work of François Sigisbert Adam as director of the French Sculpture Studio in Berlin, which Friedrich II had founded in 1747. Adam worked until 1760 in Berlin and created with the studio above all sculptures for the park Sanssouci.With the work of the French artistic claim and methodical experience in the production of marble sculptures were drawn to Berlin and thus created an important condition for the development of the Berlin Bildgauerschule in the late 18th and in the 19th century.[Saskia Huneke]