Machine learning algorithms have become widespread for a wide array of tasks. However, there is still no established way to deal with the ethical issues involved in their development and design. Some techniques have been proposed in the literature to support the reflection and/or documentation of the design and development of machine learning models, including ethical considerations, such as: (i) Model Cards and (ii) the Extended Metacommunication Template. We conducted a qualitative study to evaluate the use of these tools. We present our results concerning the use of the Model Card by participants, with the objective of understanding how these actors interacted with the relevant tool and the ethical dimension of their reflections during our interviews. Our goal is to improve and support techniques for developers to disclose information about their models and reflect ethically about the systems they design. Furthermore, we aim to contribute to the development of a more ethically informed and fairer use of machine learning.