The integration of Lean tools within Industry 4.0 environments has gained increasing relevance as companies seek to enhance productivity, improve quality, and reduce waste while navigating the challenges of digital transformation. This paper explores the application of Lean tools in the context of Industry 4.0, highlighting how traditional approaches such as Value Stream Mapping, the Pareto Chart, and the Cause-and-Effect Diagram remain valuable in identifying inefficiencies and guiding decision-making within technologically advanced industrial systems. To illustrate this synergy, a case study was carried out in the painting line of an automotive company in Portugal. A comprehensive mapping of the production process was conducted to gain a detailed understanding of its structure, constraints, and sources of variability. Lean analysis enabled the identification of recurring failures, bottlenecks, and opportunities for standardization and stabilization. Despite no immediate quantitative improvements, the actions strengthened supervision, enhanced traceability, and encouraged team involvement. Moreover, the interventions laid the groundwork for a structured path toward continuous improvement, demonstrating that Lean tools remain essential in promoting operational excellence, even within the framework of Industry 4.0. The study reinforces the view that digital technologies and Lean thinking are not mutually exclusive but rather complementary approaches that, when combined, can generate sustainable long-term benefits.