The probability P(c → D*+) that a charm quark fragments into a D*+ meson and the c → l+ semileptonic branching fraction were measured in Z0 decay into cc̄ events. From the analysis of 3.5 Million Z0 events collected from 1992 to 1995, a sample of charm meson decays with 81% cc̄ purity was selected. The product of the c → D*+ fragmentation probability times the D*+ → D0π+ branching fraction was measured to be: P(c → D*+) · BR(D*+ → D0π+) = 0.174 ± 0.010(stat) ± 0.004(syst). Using the world averaged value for BR(D*+ → D0π+), the fragmentation probability is inferred: P(c → D*+) = 0.255 ± 0.015(stat) ± 0.006(syst) ± 0.005(syst.BR). From the same sample, 1828 ± 51 identified leptons in the opposite hemisphere were selected. From this sample, the charm semileptonic branching fraction was measured to be: BR(c → l+) = 0.0958 ± 0.0042(stat) ± 0.0028(syst).