Broken Sword 5 -The Serpent's Curse - Joey Easter Egg Hidden Achievement.
3To unlock this achievement you much click on Joey the yellow robot on the window of the Tricolore cafe to the left of Le Lizard Bleu Gallery. You click on Joey everytime you come back to this screen and you must do it before you do anything else or the achievement won't unlock.
00:00 - 1. The first time you can click on Joey is when George leaves the Gallery right after the murder when you go to check out Laine's alibi. Joey should say "FOSTER! Sensors detect incoming audio source!" click again until he said "I'm your friend.Call me Joey."
00:26 - 2. The second time is when Nico comes back to the gallery and Moue is standing at the door. Click on Joey before you speak with Moue. Joey will say "Help me, Nico Collard; you're my only hope."
01:02 - 3. The third time is when George gets back from Vera Security looking for Laine. Click on Joey before going to the Cafe. This time Joey will say "Seize the day, boys."
01:24 - 4. The forth time is when Nico has let Marques into Adam's apartment and comes back to the Gallery looking for Laine. Click on Joey before speaking with Laine and he will say "All partings foreshadow the great final one."
01:43 - 5. The fifth time is when George gets back from London for the reconstruction at the Gallery. Before entering the Gallery click on Joey and he should say "Run Georgie! Run! Hide from the evil!".
02:06 - 6. The final time is after George gets the Keys from Bijou after dancing with her and heads back to the Gallery to open the safe. George will automatically start speaking with Father Simeon but after the conversation click on Joey. He should say "What do you get if you multiply six by nine?" and the achievement should unlock.
This didn't unlock for me on the first playthrough so I think the achievement may prone to glitching. I had to complete a speedrun in one sitting and it unlocked then.