Despite decades-long fascination, the difficulty of maintaining high lattice symmetry in frustrated nonbipartite S = $\frac{1}{2}$ materials that can also be made into high-quality single crystals has been a persistent challenge. We report magnetization studies of a single-crystal sample of barlowite, Cu<
sub>
4<
/sub>
(OH)<
sub>
6<
/sub>
FBr, which has a geometrically perfect kagome motif. At T ? 4.2 K and 35 ? ?<
sub>
0<
/sub>
H ? 65 T, the interlayer spins are fully polarized, and the kagome-intrinsic magnetization is consistent with a Heisenberg model having J/k<
sub>
B<
/sub>
= -180 K. Several field-driven anomalies are observed, having varied scalings with temperature. At an applied field, kagome disorder caused by the interlayer spins is smaller than that in herbertsmithite. At T ? 15 K, the bulk magnetic moment comes from the interlayer spins. An almost coplanar spin order suggests that the magnitude of in-plane Dzyaloshinskii-Moriya interaction is smaller than 0.006(6) J. On the other hand, the possibility of a spin-liquid state in the kagome lattice coexisting with ordered interlayer spins is left open.