A process for the manufacture of CF3CH═CHF and/or CF3CF═CH2 is disclosed. The process involves (a) reacting HF and chlorine and at least one halopropene of the formula CX3CCI═CCIX (where each X is independently F or Cl) to produce a product including both CF3CCI2CCIF2 and CF3CCIFCCI2F; (b) reacting CF3CCI2CCIF2 and CF3CCIFCCI2F produced in (a) with hydrogen to produce a product including both CF3CH2CHF2 and CF3CHFCH2F; (c) dehydrofluorinating CF3CH2CHF2 and CF3CHFCH2F produced in (b) to produce a product including both CF3CH═CHF and CF3CF═CH2; and (d) recovering CF3CH═CHF and/or CF3CF═CH2 from the product produced in (c). In (a), both CF3CCI2CCIF2 and CF3CCIFCCI2F are produced in the presence of a chlorofluorination catalyst consisting of (i) compositions comprising a crystalline alpha-chromium oxide where at least 0.05 atom % of the chromium atoms in the alpha-chromium oxide lattice are replaced by copper, and (ii) compositions of (i) which have been treated with a fluorinating agent.