A model-dependent amplitude analysis of the decay B0 → D(K0Sπ+π−)K∗0 is performed using proton-proton collision data corresponding to an integrated luminosity of 3.0 fb−1, recorded at √s = 7 and 8 TeV by the LHCb experiment. The CP violation observables x± and y±, sensitive to the CKM angle γ, are measured to be
x− = −0.15 ± 0.14 ± 0.03 ± 0.01,
y− = 0.25 ± 0.15 ± 0.06 ± 0.01,
x+ = 0.05 ± 0.24 ± 0.04 ± 0.01,
y+ = −0.65 +0.24
−0.23 ± 0.08 ± 0.01,
where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the D → K0Sπ+π− amplitude model. These are the most precise measurements of these observables. They correspond to γ = (80+21−22)◦ and rB0 = 0.39 ± 0.13, where rB0 is the magnitude of the ratio of the suppressed and favoured B0 → DK+π− decay amplitudes, in a Kπ mass region of ±50 MeV around the K∗(892)0 mass and for an absolute value of the cosine of the K∗0 decay angle larger than 0.4.