Abundance of C, A(C), as as function of [Fe/H]. The Sagittarius sample (blue circles) includes stars from the final selection made in Sect. 2.3, from Chiti & Frebel (2019), and from Chiti et al. (2020). The DGs compilation (orange circles) is from Lucchesi et al. (2024). Inner Galaxy stars (grey circles) are selected from Ardern-Arentsen et al. (2024) to have good quality of the AAT spectra and good FERRE measurements as in our sample. Star P185855-301522 (red pentagon) is analysed in Sestito et al. (2024b) and confirmed to be CEMP-s from high-resolution spectroscopy. Star P190122-304744 (purple square) is one of the two cool CEMP candidates discussed in Sect. 5.2. Horizontal green dashed line tentatively separates CEMP-s from CEMP-no as in Yoon et al. (2016). Stars on the left of the dashed black line have [C/Fe] > +0.7 as defined in Aoki et al. (2007). The dashed red line denotes the tentative new limit for CEMP in Sgr ([C/Fe] = +0.35). Sgr stars with [C/Fe] > +0.35 are displayed with their errorbars to highlight that they are significantly distant from the bulk of the system’s distribution.