International audienceA study of Leibniz bialgebras arising naturally through the double of Leibnizalgebras analogue to the classical Drinfeld’s double is presented. A key ingredient of ourwork is the fact that the underline vector space of a Leibniz algebra becomes a Lie algebraand also a commutative associative algebra, when provided with appropriate new products.A special class of them, the coboundary Leibniz bialgebras, gives us the natural frame-work for studying the Yang-Baxter equation (YBE) in our context, inspired in the classicalYang-Baxter equation as well as in the associative Yang-Baxter equation. Results of theexistence of coboundary Leibniz bialgebra on a symmetric Leibniz algebra under certainconditions are obtained. Some interesting examples of coboundary Leibniz bialgebras arealso included. The final part of the paper is dedicated to coboundary Leibniz bialgebrastructures on quadratic Leibniz algebras