  We present near-IR spectroscopy of the massive intermediate age star cluster
W3 in the merger remnant galaxy NGC 7252, obtained with the NTT telescope. This
cluster has an age when the integrated near-IR properties of a stellar
population are dominated by the cool and luminous AGB stars. We compare the
data with instantaneous curst model predictions from new evolutionary synthesis
models that include: (1) the computation of the evolution through the TP-AGB
for low- and intermediate-massive stars, with the initial mass and metallicity
dependent formation of carbon stars; (2) spectroscopic data from a new stellar
library in which differences betwenn static giants, vriable O-rich TPAGB stars
and carbon stars are accounted for. The comparison of the data to the models
clearly shows that carbon stars are present: for the first time, carbon star
spectral features are thus detected directly outside the Local Group (abriged)
