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SrTiO<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> is an insulating material which, using chemical doping, pressure, strain or isotope substitution, can be turned into a ferroelectric material or into a superconductor. The material itself, and the two aforementioned phenomena, have been subjects of intensive research of Karl Alex Müller and have been a source of inspiration, among other things, for his Nobel prize-winning research on high temperature superconductivity. An intriguing outstanding question is whether the occurrence of ferroelectricity and superconductivity in the same material is just a coincidence, or whether a deeper connection exists. In addition there is the empirical question of how these two phenomena interact with each other. Here we show that it is possible to induce superconductivity in a two-dimensional layer at the interface of SrTiO<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> and LaAlO<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> when we make the SrTiO<inline-formula><math display="inline"><semantics><msub><mrow></mrow><mn>3</mn></msub></semantics></math></inline-formula> ferroelectric by means of <inline-formula><math display="inline"><semantics><msup><mrow></mrow><mn>18</mn></msup></semantics></math></inline-formula>O substitution. Our experiments indicate that the ferroelectricity is perfectly compatible with having a superconducting two-dimensional electron system at the interface. This provides a promising avenue for manipulating superconductivity in a non centrosymmetric environment.