  Well-studied very metal-poor (VMP, [Fe/H] < -2 ) stars in the inner Galaxy
are few in number, and they are of special interest because they are expected
to be among the oldest stars in the MilkyWay. We present high-resolution
spectroscopic follow-up of the carbon-enhanced metal-poor (CEMP) star
Pristine_184237.56-260624.5 (hereafter Pr184237) identified in the Pristine
Inner Galaxy Survey. This star has an apocentre of about 2 kpc. Its atmospheric
parameters (Teff = 5100 K, log g = 2.0, [Fe/H] = -2.60) were derived based on
the non-local thermodynamic equilibrium (NLTE) line formation. We determined
abundances for 32 elements, including 15 heavy elements beyond the iron group.
The NLTE abundances were calculated for 13 elements from Na to Pb. Pr184237 is
strongly enhanced in C, N, O, and both s- and r-process elements from Ba to Pb;
it reveals a low carbon isotope ratio of 12C/13C = 7. The element abundance
pattern in the Na-Zn range is typical of halo stars. With [Ba/Eu] = 0.32,
Pr184237 is the first star of the CEMP-r/s subclass identified in the inner
Galaxy. Variations in radial velocity suggest binarity. We tested whether a
pollution by the s- or i-process material produced in the more massive and
evolved companion can form the observed abundance pattern and find that an
i-process in the asymptotic giant branch star with a progenitor mass of 1.0-2.0
Msun can be the solution.
