The spoon is from Jean-Pierre-Louis RAMU-Dufour (1796-1852). The other mark is the "fineness mark". 3 is for 3eme titre, so 800/1000 purity. In the System in use in Geneva between 1815 and 1881, normally a lions head was used on the 800 purity mark. However, also the makers Initials were in use. So RD stands for RAMU-DUFOUR.
You can date your Piece around 1850.