I dont think it has 15 pop, we are nto sure that 15 represents population. It may do though.
Hmm I dunno, it seems clear to me that it is 15 pop comparing it to the Rome shots where sci=pop of 13. Berlin shows the 15sci, has the 15 icon in the middle. But yea like I said if you count the tiles being worked you can see 8 which matches where it says "8 citizens", then adding the 4 specialists = 12, with 3 either unassigned or affected by unhappiness.
Edit: then again I only count 18 food from the tiles being worked.. makes more sense to have 8 citizens * 2 = 16food with 1.5 leftover from something I am missing hehe.
or it's 1 food per pop instead of 2 which would leave +3 food at 15citizens.
But if it is 8pop, that doesnt work out either with the specialists since you can see the tile yields that are highlighted from being worked.