Flat-band (FB) systems originating from special lattice geometry like in kagome metals as well as localized orbitals in materials such as heavy-fermion (HF) compounds have attracted intensive interest due to their band topology and strong electron correlation effects, leading to emergent quantum states of matter. However, how these two distinct types of FBs coexist and interact within a single material remains largely unexplored. Here, we report that ${\mathrm{YbCr}}_6{\mathrm{Ge}}_6$, hosting both a Cr kagome lattice and localized Yb $4f$ electrons, exhibits HF behavior and has an antiferromagnetic ground state with a transition temperature $T_N$ = 3 K. Angle-resolved photoemission spectroscopy (ARPES) reveals the coexistence of Cr kagome-derived and Yb $4f$-derived FBs near the Fermi level $E_{\mathrm{F}}$. Photon-energy-dependent ARPES measurements distinguish the bulk dispersive kagome-derived bands from the nearly momentum-independent Yb $4f$ states, while clear spectroscopic signatures of $c\text{−}f$ hybridization are observed between the Yb $4f$ FBs and kagome-derived conduction bands. The high density of states associated with the Cr kagome FB and the $c\text{−}f$ hybridization provide microscopic insight into the enhanced electronic correlations and magnetic ordering in ${\mathrm{YbCr}}_6{\mathrm{Ge}}_6$. Our findings establish ${\mathrm{YbCr}}_6{\mathrm{Ge}}_6$ as a promising platform for exploring the interplay between kagome FB physics and strong $f$-electron correlations.

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• Flat bands
• Magnetism
• Heavy-fermion systems
• Kagome metal
• Strongly correlated systems
• Angle-resolved photoemission spectroscopy
• Magnetization measurements
• Resistivity measurements
• Specific heat measurements